Response to sudden torques about ankle in man: myotatic reflex.

1. Sudden dorsiflexions and plantarflexions of the foot were imposed on normal human subjects under various states of voluntary activity. 2. Under conditions of constant muscle contraction, the myotatic reflex in soleus and lateral gastrocnemius muscles is linearly and highly correlated with the rate of muscle stretch. The slope of this curve characterizes part of the reflex arc "gain." 3. The gain is linearly proportional to the level of tonic voluntary activation. 4. The gain is reduced by tonic contraction of antagonists. 5. The above statements can be summarized by the following equation (formula: see text), where d theta/dt is the rate of joint rotation. Ts and Tat are measures of voluntary contraction (tension) of all the extensor and flexor muscles acting at the ankle. The term S represents the level of preexisting spinal excitability that can be altered by prior instruction to the subject. 6. A phasic voluntary contraction of the soleus muscle, which leads to muscle shortening, will alter the reflex gain. The gain initially increases with increasing rates of shortening, but at higher rates the gain is reduced. This is in contradiction to the observation for tonic activation as stated above and may be due to an inability of the coactivated fusimotor system to produce sufficiently rapid cocontraction of the spindle fibers. 7. During lengthening of a muscle caused by voluntary contraction of its antagonists, the myotatic reflex gain is reduced. 8. The above facts are interpreted to imply that a functional role for the myotatic reflex in the leg extensors is limited to conditions of postural maintenance or slow, precise movement. During rapid movement, the myotatic reflex is ineffective and load-compensating reactions are mediated by longer latency loops. 9. The duration of the myotatic reflex EMG is from 10 to 40 ms, too brief to be a simple response to a velocity-sensing receptor organ. Either the response is in large measure due to the initial burst of spindle activity that occurs at the start of a ramp stretch, or motoneuron pool dynamics act as a high-pass filter on afferent inputs. 10. In the anterior tibial muscle, the relationships between stretch velocity and reflex amplitude and tonic voluntary contraction and reflex gain are qualitatively similar to those found in the ankle extensors.


Slowly adapting receptors in cat hip joint.

1. The activity of slowly adapting joint receptors was recorded from fibers of the posterior articular nerve of the hip in deeply anesthetized cats. The static stimulus was any position of the femur maintained at least 2 min after passive displacement. Most of the fibers are active in all the positions where the femur may be placed. Modulation in the discharge frequency occurs in any axis of displacement, and higher activity is recorded at extreme positions. The maximal discharge may be reached in several positions of the femur far away from one another. 2. Adaptation to static stimuli occurs in all the receptors. Joint receptors fire at very regular, steady rates; the mean coefficient of variation was 0.079. 3. In most of the receptors, when the femur is displaced along a single axis, the frequency of discharge varies as a monotonic function of joint position. This relationship could be described either by linear and logarithmic or by linear and power functions, according to the criteria adopted to indicate the intensity of the stimulus. 4. Repetition of identical static stimuli results in different responses. 5. The static properties of the receptors are not modified by the section of periarticular muscles. 6. Hip joint receptors are able to code hip joint position.


Anomalous inward rectification in hippocampal neurons.

1. Anomalous rectification occurred in 54 of 56 hippocampal CA1 neurons studied in vitro. This phenomenon is characterized by a progressive increase in input resistance with membrane depolarization. An average increase in membrane resistance of 45% occurred over a 15-mV region of membrane potential immediately subthreshold to cellular firing. 2. Both Mn2+, a Ca+ antagonist, and tetrodotoxin (TTX), a neurotoxin that blocks regenerative Na+ currents, eliminated anomalous rectification. Ba2+, which can both contribute to intracellular cation influx as well as reduce K+ conductance, increased the magnitude of anomalous rectification. The observations are indirect evidence indicating that a Ca2+-Na+ current may produce the inward-going rectification. 3. Enhancement of anomalous rectification by Ba2+ was associated with the onset of membrane oscillations and spontaneous bursts of repetitive discharges. The magnitude of anomalous rectification may be one factor that predisposes some cortical neurons to bursting behavior.


Treatment of carotid-cavernous fistulas by cavernous sinus occlusion.

The author reports the occlusion of 33 carotid-cavernous fistulas in 31 patients using thrombogenic techniques. In one patient the carotid artery had been occluded previously, in one it was occluded deliberately, and with 31 fistulas it was preserved. There was no mortality and virtually no morbidity.


Intraoperative evaluation of cerebral hemodynamics using directional Doppler technique. Part 1: Arteriovenous malformations.

The use of a pulsed echo Doppler technique during surgery for cerebral arteriovenous malformation is described. The equipment and the methods employed are presented. The main advantages are easy determination of flow direction and pattern of the vasculature involved, allowing a precise discrimination between inflow and outflow channels. Deep-seated malformations, not visible at the brain surface, can be located with the Doppler technique. The ultrasound probe was placed on the brain surface with a slight pressure on the intact pia mater. The precise direction and depth of the malformation could be determined in relation to the recording site. This facilitated the planning of cortical incisions, identification of vessels involved, and the vascular procedure to be employed.


An analysis of follow-up results of 1000 intracranial saccular aneurysms with definitive surgical treatment.

The authors report a follow-up review of 1000 cases of intracranial definitive surgery for saccular aneurysms. The prognosis for such surgical cases is discussed. Postoperative results at least 6 months after discharge from the hospital were analyzed in 876 (93.3%) of the 939 surviving patients. The longest follow-up period was 14 years and 5 months, with an average of 3 years and 7 months. At the time of discharge, there were 543 excellent results, 186 good, 117 fair, 93 poor, and 61 deaths. The chief findings were as follows: 1) Most of the patients determined as "excellent" or "good" at discharge were able to return to normal life; most of the deaths or instances of worsened condition found in the follow-up study were due to new lesions. 2) Fully 62% of the cases determined as "fair" at discharge were found in an improved state at the follow-up study, having returned to normal life. 3) Only 19% of cases determined as "poor" at discharge had improved to the point where a return to normal life was possible, the majority having died or remaining in poor condition.


Individual variability in cortical localization of language.

Individual variability in the localization of language, as measured by object-naming, was assessed for left lateral peri-Sylvian cortex with a multi-sample technique of stimulation mapping at a constant current. This study was performed during craniotomy under local anesthesia in 10 patients with medically intractable epilepsy and the usual pattern of left brain dominance for language. A high degree of variability in the exact location of naming was present. Only one area, a small portion of the third frontal convolution immediately in front of the motor strip, showed naming changes in all patients in whom it was sampled. This area is considerably smaller than the classical Broca's area. Elsewhere in language cortex, including all parts of the posterior language area, there was considerable individual variability. Because of this, the classical model of language localization is an inaccurate basis for establishing the risk of aphasia in surgical therapy of dominant hemisphere peri-Sylvian lesions in this and related patient populations. Rather, that risk should be assessed from the individual localization of language, established by the multisample technique of stimulation mapping.


Total removal of acoustic neurinomas.

The authors analyze the results of total removal of acoustic neurinomas in 120 patients operated on between January, 1967, and January, 1976. The facial nerve was preserved after surgery in 65 patients (54.2%). The use of microsurgical techniques in the last 3 years of study permitted preservation of the seventh nerve in 26 of 35 operated patients (74.3%). Of 103 patients examined postoperatively, 96 retained their full or partial capacity for work (93.2%). Ten patients (8.3%) died after surgery. In the last 3 years, 35 patients were operated on without a single death.


Scoliosis and hydrocephalus in myelocele patients. The effects of ventricular shunting.

Developmental scoliosis is a common cause of increasing disability and deformity in long-term myelocele survivors, and is believed to result from a paralytic collapsing spine. The possible etiological role of compensated hydrocephalus and hydromyelia was assessed by determining the effect of ventricular shunting on 11 myelocele patients with developmental scoliosis. After successful shunting, one patient with a 47 degrees curve continued to deteriorate. Three cases with curves greater than 60 degrees were stabilized for short periods, but eventually required spinal fusion. Seven cases with curves less than 55 degrees were improved from a mean scoliosis of 29 degrees to 13 degrees during a 20-month follow-up period. Several patients had pre-existing shunts that were found to be non-functional on shuntogram. These findings suggest that the spinal complications of hydrocephalus may be more common than previously recognized in myelocele patients and that advanced developmental scoliosis may be avoided by early recognition and ventricular shunting.


Long-term results after ventriculoatrial and ventriculoperitoneal shunting for infantile hydrocephalus.

This series of 228 patients with infantile non-neoplastic hydrocephalus who received either a ventriculoatrial (VA) or a ventriculoperitoneal (VP) shunt before 2 years of age was followed for an average of 7 years, and the results with the two types of shunt were compared. Mortality and infection rates were similar for both groups of patients, but children with VP shunts required significantly fewer revisions and had a much greater likelihood of not having any revisions during the follow-up period. Late complications occurred more frequently with VA shunts and were more serious. It is concluded that VP shunts offer significant advantages over VA systems in this population.


Craniofacial growth following experimental craniosynostosis and craniectomy in rabbits.

Premature fusion of the coronal suture was produced in 9-day-old rabbits by immobilization of the suture area bilaterally with methyl-cyanoacrylate adhesive. The effects of suture fusion and its surgical release on suture growth and on skull morphology were evaluated by radiographic cephalometry. Immobilization resulted in significant changes in the angular dimensions in the vault toward an anteroposterior shortening. No permanent deformity was observed in the angular relationship between the cranial base and the facial skeleton. Craniectomy at 30 days, when a skull deformity had been established, resulted in rapid separation of the bones at the suture site which returned the deformed skull to a normal configuration by 90 days of age. Surgical removal of a normal suture in a control group also resulted in accelerated separation of the bones at the excised suture site, but it was less than after removal of an immobilized suture. The experimental data indicate that premature fusion of rapidly growing sutures results in consistent skull deformity. Early release of the fusion, when this is the primary abnormality, will result in spontaneous correction of the deformity.


Loss of autoregulation and posttraumatic ischemia following experimental spinal cord trauma.

Blood flow in the dorsolateral funiculus of the cat thoracic spinal cord was studied after severe experimental cord injury, using a modification of the hydrogen clearance technique. Autoregulation was intact during the initial 60 to 90 minutes after cord injury, but was then lost coincident with the onset of ischemia. The data suggest that the ischemic response to spinal cord injury is mediated both by the loss of autoregulation and by relative vasoconstriction of the resistance vessels. Therapeutic intervention aimed at maintaining perfusion during the early posttraumatic period may prove of value in reversing or limiting some elements of dysfunction due to the secondary injury of ischemia.


Alteration of posttraumatic ischemia in experimental spinal cord trauma by a central nervous system depressant.

Blood flow after severe experimental injury to the thoracic spinal cord was studied in cats, using a modification of the hydrogen clearance technique. Gamma hydroxybutyrate, a central nervous system depressant, was shown to markedly alter the ischemic response to injury if given during the early posttraumatic period. Other vasoactive drugs investigated had no effect on posttraumatic ischemia. Therapeutic intervention during the early posttraumatic period aimed at increasing blood flow while decreasing the metabolic requirements of the injured cord may prove of value in reversing or limiting some elements of long-tract dysfunction due to the secondary ischemic insult.


Early diagnosis of delayed posttraumatic intracerebral hematomas.

Nine cases of delayed posttraumatic intracerebral hematomas (DTICH) were found retrospectively among 656 patients with closed head injuries admitted to the Hennepin County Medical Center in a 12-month period. All cases had severe head injuries sustained with the head in motion. The interval from cranial injury to diagnosis of DTICH by computerized tomography (CT) varied from 8 hours to 13 days. Eight patients were comatose on admission, three had focal seizures, and three had focal findings. The diagnosis was made on repeat CT scans obtained because of the development of focal findings in four cases, lack of improvement in four cases, and general neurological deterioration in one case. Four patients had initially negative CT scans. Four demonstrated only extracerebral hematomas on initial CT scan. One patient showed intracerebral hematoma on the initial scan followed by new hematomas on repeat study. The cases presented are discussed in light of pertinent literature.


Pathology of an arachnoid cyst. Case report.

Accidental death brought to autopsy a 19-year-old girl with asymptomatic arachnoid cyst which had expanded from the region of the interpeduncular cistern so as to replace the third ventricle and extend into both alteral ventricles. Associated with this expansion was a significant degree of hydrocephalus, compression of the walls of the lateral ventricle, and obliteration of the normal structures of the floor of the third ventricle. The histological structure of the cyst wall and its relationship to the normal arachnoid are defined and found to consist of a reduplication of the normal arachnoid membrane resulting in a space within the arachnoid tissue. It is suspected but not proven that the cyst was congenital, resulting from an abnormality in development. Some suggestions are offered regarding the mechanism for its enlargement.


Vasospasm following transcranial removal of large pituitary adenomas. Report of three cases.

The authors report three cases of cerebral vascular spasm following transfrontal removal of large pituitary neoplasms. One patient awakened from surgery hemiparetic, but has since recovered. A second patient developed hemiparesis with confusion on the fifth postoperative day and eventually died. The third patient developed hemiplegia on the tenth postoperative day, but recovered completely. Vascular spasm was documented angiographically in all three cases. Possible mechanisms underlying this unusual complication are discussed.


Meningioma of the anterior part of the third ventricle. Case report.

The authors present a case of meningioma located in the anterior part of the third ventricle. The mass was successfully removed through a right-sided transventricular approach after stereotaxic biopsy. A review of the relevant literature is included.


Extradural spinal involvement by gout. Case report.

A case of extradural gouty tophus in the lumbar region in a teen-age girl is presented as an addition to the differential diagnosis of erosive lesions of the spinal canal.


Subependymal giant-cell astrocytoma. Case report with ultrastructural study.

A 13-year-old boy presented with an obstructive left lateral intraventricular mass. Pathological examination revealed a subependymal giant-cell astrocytoma. Further clinical investigation confirmed the diagnosis of tuberous sclerosis. Ultrastructural examination confirmed previously reported features of this tumor. Tumor cells containing large dense granulated bodies and dense-core vesicles, not previously described in this tumor, were identified.


Primary intracranial endodermal sinus tumor. Case report.

Endodermal sinus tumor (yolk sac carcinoma), a germinal neoplasm, is rarely primary in the cranial cavity. The authors add a third case with the tumor located in the anterior third ventricular (suprasellar) region to the literature. Seventeen previously reported intracranial cases, mostly in the pineal region, are briefly reviewed.


Bilateral trigeminal neurofibrosarcoma. Case report.

An autopsied case of bilateral trigeminal neurofibrosarcoma is reported. The right-sided inferior alveolar tumor was treated surgically and subsequently irradiated. There was no local recurrence during the ensuing 4 years. Two years after excision of that tumor, a left-sided trigeminal neurofibrosarcoma was subtotally removed. Two years later this same tumor was found to have extensively invaded the pons.


Arterial cross compression of the trigeminal nerve at the pons in trigeminal neuralgia. Case report with autopsy findings.

The autopsy findings in a patient with trigeminal neuralgia who died from unrelated causes are presented. Arterial cross compression of the appropriate trigeminal nerve at the pons was demonstrated. The relationship of arterial cross compression to trigeminal neuralgia is briefly discussed.


Subdural hematoma in an adult following a blast injury. Case report.

A case is reported of chronic subdural hematoma in a civilian who was injured when a pipe exploded while being cleaned by air blasting. The literature regarding the pathogenesis of blast injury is reviewed.


Fenestrated basilar artery with an associated saccular aneurysm. Case report.

A patient who presented with a subarachnoid hemorrhage was found to have a saccular aneurysm arising from the proximal basilar artery. The aneurysm was bilobed, directed anteriorly and inferiorly, and associated with a proximal fenestrated segment of the basilar artery.


Factors influencing future progress in neurosurgery.

The ever-widening horizons in the neurosciences are noted by the author. Maintenance of the bridges between research and clinical practice will result in improved therapy. Research interest is expanding, and involvement by neurosurgeons and neurosurgical training programs is vital for future progress. Techniques are required to evaluate and assess new surgical procedures that evolve from research endeavors.


Superficial temporal artery to middle cerebral artery anastomosis. Intraoperative evaluation by fluorescein angiography and xenon-133 clearance.

Fluorescein angiography and xenon-133 (133Xe) clearance studies were performed during surgery on 15 patients who were undergoing superficial temporal artery (STA) to middle cerebral artery (MCA) anastomosis. Fourteen patients had occlusive disease of the internal carotid artery (ICA), and one patient had severe stenosis of the MCA. Before anastomosis, fluorescein angiography showed slow filling of the MCA branches through collateral channels. Focal areas of impaired microcirculatory filling and washout were seen in the territory of severely sclerotic cortical arteries. The findings of preanastomotic 133Xe clearance studies were variable and a uniform pattern of regional cerebral blood flow (rCBF) changes was not defined. In 55% of the patients, rCBF was reduced to 25 ml/100 gm/min or less at one or more detector sites. Fluorescein angiography provided an immediate assessment of anastomotic patency and clearly displayed the distribution of blood entering the epicerebral circulation through the STA. In 67% of patients, multiple MCA cortical branches filled with fluorescein, whereas in 33% filling was restricted to the receptor artery territory. An immediate, substantial (greater than or equal to 15 ml/100 gm/min) increase in rCBF was demonstrated in 73% of patients after anastomosis. The rCBF changes were consistently better in patients with donor and receptor arteries greater than 1 mm in diameter. Redistribution of collateral input acted to increase rCBF in areas distant from the anastomotic site. Some improvement in fluorescein circulation and rCBF also was seen in cortex supplied by sclerotic MCA branches.


Intraoperative evaluation of cerebral hemodynamics using directional Doppler technique. Part 2: Saccular aneurysms.

The use of a pulsed echo Doppler technique during procedures for occlusion of intracranial aneurysms is described. Saccular aneurysms can be located with reference to probe position and depth setting. Tracings of intra-aneurysmal flow are presented, and the characteristic flow pattern is disucssed. Special emphasis has been placed on the parent artery flow, particularly the effect of lumen reduction on flow velocity. Results of flow velocity studies on the cognate (direct) and collateral flow in the middle cerebral artery and the proximal anterior cerebral artery are presented and discussed.


Regional cerebral blood flow in patients with ruptured intracranial aneurysms.

Eighty-five studies of regional cerebral blood flow (rCBF) were performed on 49 patients with ruptured intracranial aneurysms. The changes in rCBF were analyzed under various pathophysiological conditions, The degree of flow abnormalities correlated well with the clinical severity of neurological deficits. All of the patients with diffuse vasospasm of severe grade, to less than half of their control value, showed focal areas of decreased flow below 30 ml/100 gm/min, in addition to a reduction in mean CBF. The relief or disappearance of vasospasm in angiograms was followed by the increase of rCBF in the ischemic focus and mean CBF. Marked reduction in rCBF was found in patients with intracerebral hematoma and ventricular dilatation. Impaired CO2 response and autoregulation were found in patients with severe neurological deficits, a severe degree of vasospasm and marked depression of CBF. In this series direct operation was delayed in patients with impaired vascular reactivity as well as marked decrease of mean CBF below 30 ml/100 gm/min; good clinical results were obtained in thses patients.


Monitoring of cortical excitability during induced hypotension in aneurysm operations.

The electrical excitability of the cortex was monitored during craniotomy in 10 patients with ruptured aneurysms, to test their ability to tolerate hypotensive anesthesia. Excitability was assessed by measuring the direct cortical response, a response evoked and recorded from the surface of the brain. Previous animal experiments had shown that this response can be used as an index of cerebral blood flow. In the 10 patients the response progressively declined as the blood pressure was lowered and increased when the pressure was restored. Observation of the direct cortical response during aneurysm operations is a practical method for evaluating the electrophysiological responsiveness of the cortex during hypotension, and the authors suggest that decreases in the amplitude of the response are related to decreased in local cerebral blood flow.


Halo immobilization of cervical spine fractures. Indications and results.

Thirty-three patients with a spectrum of cervical spine fractures or subluxations were treated with immobilization by a halo apparatus. All spines were assumed to be unstable because of the nature of the fracture or because of a subluxation noted on spine films. Treatment consisted of immobilization and fracture reduction followed by application of a halo plaster cast or molded halo plastic vest. Patient acceptance was high. Complications were few and minor. No patient experienced neurological deterioration during treatment. Reduction was well maintained during an average halo immobilization period of over 3 months. Use of the halo resulted in healing of bone and ligament and restoration of stability in 85% of the patients. Halo immobilization was efficacious in the treatment of odontoid and hangman's fractures as well as complex fractures involving multiple areas of a single vertebra. It was also used successfully as an adjunct to posterior cervical fusion. Although several patients with subluxations or angulation without bone injury were treated successfully, two of the four therapy failures occurred in this group of patients, and the halo must be used with caution in this clinical setting. Contraindications to the use of the halo include complete cervical spinal cord injury with anesthetic skin, tomographic and/or myelographic evidence of disc or bone within the spinal canal, and unsatisfactorily reduced subluxations. The halo has provided more effective and reliable immobilization than other orthoses. It is an acceptable alternative to cervical fusion for the achievement of stability in a wide variety of cervical spine fractures and dislocations avoiding both the short-term and perhaps long-term complications of spinal fusion.


Neurological prognosis after traumatic quadriplegia. Three-year experience of California Regional Spinal Cord Injury Care System.

Between January, 1974, and December, 1976, 123 patients with traumatic quadriplegia were admitted to the California Regional Spinal Cord Injury Care System. The spinal cord injury resulted from gunshot wounds in five, from a stab wound in one, from neck injuries with no bone damage seen on x-ray studies in 10, and from fracture dislocations of the cervical spine in 107. One-year following-up information was available on 114 patients. Neurological impairment using the Frankel classification system was compared at 72 hours postinjury to the 1-year follow-up examination. Fifty of 62 patients with complete injury at 72 hours were unchanged at 1 year. Five of these 62 patients had developed motor useful function in the legs or became ambulatory by 1 year, but all had sustained serious head injuries at the time of their trauma making initial neurological assessment unreliable. Ten percent of all cases had combined head injury impairing consciousness. Among 103 cognitively intact patients, none with complete injury at 72 hours were walking at 1 year. Of patients with sensory incomplete functions at 72 hours postinjury, 47% were walking at 1 year; 87% of patients with motor incomplete function at 72 hours postinjury were walking at 1 year. Spinal surgery during the first 4 weeks postinjury did not improve neurological recovery. A method of analyzing neurological and functional outcomes of spinal cork injury is presented in order to more accurately evaluate the results of future treatment protocols for acute spinal injury.


Craniopharyngiomas in childhood. A rational approach to treatment.

The authors review 60 children who presented with craniopharyngiomas. Patients were treated by either 1) cyst aspiration followed by deep x-ray therapy (DXT), 2) radical excision, 3) incomplete tumor excision, or 4) incomplete excision followed by DTX. Symptomatic clinical recurrence signified failure of treatment. Of the patients treated by cyst aspiration and DXT, 50% experienced recurrence (mean time after treatment, 4.4 years), while recurrences occurred in 23% undergoing radical excision (mean time, 2.4 years). Symptomatic recurrences occurred in 78% treated by incomplete removal only (mean time, 2.2 years). No recurrences have occurred in seven patients whose incomplete removal was followed by DTX. The authors conclude that radical excision is most likely to produce survival free of recurrence. When radical excision is not possible, DXT appears to provide an additional effect on preventing tumor regrowth. Characteristics of craniopharyngiomas favoring radical excision are also discussed.


Studies of experimental cervical spinal cord transection. Part II: Plasma norepinephrine levels after acute cervical spinal cord transection.

Plasma concentrations of norepinephrine (NE) were measured by a radioenzymatic assay technique before and serially after laminectomy at the C-6 level in 14 anesthetized dogs. In half the animals, no further procedures were carried out (control group); in the other dogs, cervical cord transection was performed in addition to laminectomy (experimental group). Mean plasma NE levels were similar in both groups after laminectomy and before cord interruption. In the control group, NE levels increased gradually for 2 hours after the procedure. In the group with cord transection, however, NE rose immediately after transection to 267% of the baseline value, then fell to 25% of the plasma NE level in the control group at 30 minutes, 29% at 60 minutes, and 15% at 120 minutes. Cervical spinal cord transection, therefore, results in an abrupt but short-lived increase in plasma NE concentrations. These changes in plasma NE levels may explain, at least in part, the hemodynamic alterations and the acute central hemorrhagic necrosis that occur after high spinal cord trauma.


Selective traumatic infarction of the human anterior hypothalamus. Clinical anatomical correlation.

A case of assult with bilateral manual avulsion of the eyes was followed by highly selective infarction of the anterior hypothalamus. The hypothalamic infarction occurred as a result of avulsion of part of the optic chiasm together with the anterior perforating arteries passing through it; Following this assault, symptoms of hypothalamic dysfunction included altered thermoregulation, alternating diabetes insipidus, and inappropriate antidiuretic hormone (ADH) secretion, altered patterns of sleep and arousal, and changing cardiac arrhythmias. The case casts light upon the vascular supply of the human hypothalamus and on the degree of localization existing for various hypothalamic functions.


Tetraplegia secondary to cervical sarcoidosis. Case report.

This is the report of a case of vertebral sarcoidosis causing collapse of cervical vertebrae with resulting tetraplegia. The patient was successfully treated by decompression and subsequent anterior removal of the invaded three vertebral bodies, followed by an autologous bone graft.


Reconstruction of the atlas and axia with wire and acrylic after metastatic destruction. Case report.

The authors describe a method of C1-2 reconstruction by means of wires and acrylic in a patient with metastatic destruction from carcinoma of the rectum. A huge upper cervical tumor together with involved bone had been removed at an earlier operation.


Agenesis of parietal bones with restoration of the cranial vault. Case report.

Complete agenesis of both parietal bones was found as a single anomaly in an otherwise healthy boy. The defect in the cranial vault was restored with performed methyl methacrylate onlay plates.


Surgical removal of bilateral papillomas of the choroid plexus of the lateral ventricles with resolution of hydrocephalus. Case report.

The authors report a patient with bilateral papillomas of the choroid plexus of the lateral ventricles with documentation of cerebrospinal fluid (CSF) hypersecretion causing hydrocephalus. Special attention is given to the large volume of CSF produced by these tumors (removal of one tumor reduced CSF outflow by one-half) and to the fact that CSF diversion was not required after both tumors were removed. Since tumor removal alone was sufficient to stop the progression of hydrocephalus, we feel that this case supports the concept that elevated CSF production by itself is sufficient to cause hydrocephalus in patients with papillomas of the choroid plexus.


Surgical postoperative bleeding associated with aspirin ingestion. Report of two cases.

Two patients are reported in whom repeated postoperative hematomas appeared to be secondary to aspirin-induced platelet defect. Routine bleeding and clotting studies will not demonstrate this platelet-induced coagulopathy. A previous history of massive aspirin ingestion makes such a coagulopathy a serious consideration, but the platelet defect may occur with small doses of aspirin. Such aspirin ingestion should be viewed with great concern by the neurosurgeon. The defect is treatable by platelet transfusion.


Transient hemiparesis: a rare manifestation of diphenylhydantoin toxicity. Report of two cases.

Among the common side effects of diphenylhydantoin (DPH) overdose, the most frequently encountered neurological signs are those of cerebellar dysfunction. Very rarely, the toxic neurological manifestations of this drug are of cerebral origin. Two patients are presented who suffered progressive hemiparesis due to DPH overdose. Both had brain surgery before DPH treatment. It is assumed that patients with some cerebral damage are liable to manifest DPH toxicity as focal neurological signs.


Radionuclide left ventricular dV/dt for the assessment of cardiac function in patients with coronary disease.

To investigate potential uses of left-ventricular (LV) systolic ejection rate (LV dV/dt) in the evaluation of LV function, we examined the effect of exercise, angiotensin, and leg raising on LV ejection fraction and LV dV/dt in patients with coronary-artery disease. The following observations were made: a) LV ejection fraction and dV/dt changed proportionately, but in opposite directions, during supine exercise; b) LV ejection fraction and dV/dt decreased to a similar extent during angiotensin infusions; and c) LV ejection fraction and dV/dt were unchanged by leg raising. The changes in peak and mean LV dV/dt were similar. Regardless of the physiologic state, peak LV dV/dt occurred during the first third of systole. These data imply that in this population there were no specific advantages of LV dV/dt over LV ejection fraction in the evaluation of LV performance.


Computer-assisted static/dynamic renal imaging: a screening test for renovascular hypertension?

Computer-assisted static/dynamic renal imaging with [197Hg] chlormerodrin and [99mTc]pertechnetate was evaluated prospectively as a screening test for renovascular hypertension. Results are reported for 51 patients: 33 with benign essential hypertension and 18 with renovascular hypertension, and for 21 normal controls. All patients underwent renal arteriography. Patients with significant obesity, renal insufficiency, or renoparenchymal disease were excluded from this study. Independent visual analyses of renal gamma images and time-activity transit curves identified 17 of the 18 patients with renovascular hypertension; one study was equivocal. There were five equivocal and three false-positive results in the essential hypertension and normal controls groups. The sensitivity of the method was 94% and the specificity 85%. Since the prevalence of the renovascular subset of hypertension is approximately 5%, the predictive value is only 25%. Inclusion of computer-generated data did not improve this result. Accordingly, this method is not recommended as a primary screening test for renovascular hypertension.


Renographic evaluation of kidney preservation with chlorpromazine.

The effect of chlorpromazine pretreatment of kidneys then damaged by warm ischemia was investigated. The ischemia was inflicted on rabbit kidneys by renal arterial occlusion of 1 1/2 and 3 hours' duration after contralateral nephrectomy. Pretreatment with chlorpromazine, 3.5 mg/kg, was given intravenously before arterial clamping. I-125 Hippuran renography was performed before clamping, immediately after clamp release, and at 2, 4, 6, and 14 days later. Serum creatinine and survival rate were followed. Comparison with untreated control groups was made. The effect on tubular function was investigated by measuring I-125 Hippuran uptake in pretreated slices of renal cortex (compared with untreated contralateral kidney) 48 hr after circulation was restored to the ischemic kidney. Chlorpromazine pretreatment improved recovery from ischemic damage: the renograms showed improved Hippuran uptake after clamp removal, and return to normal was faster. Survival rate after 3 hr of ischemia increased from 1/10 to 6/10 in the pretreated group, and serum creatinine recovered earlier. Hippuran uptake in slices of cortex showed no significant improvement because of pretreatment. It is concluded that the beneficial effect of chlorpromazine pretreatment must be because of decreased vascular resistance, leading to long-lasting increased postischemic renal blood flow.


In vivo measurement of liver perfusion in the normal and partially hepatectomized rat using Tc-99m sulfur colloid.

A nonsacrificial technique for measurement of liver perfusion in rats using Tc-99m sulfur colloid and gamma camera with computer system is described. The results of measurement in normal rats and at various stages after partial hepatectomy are presented and are compared with results obtained by workers using other techniques. The method reported here is simpler to perform than those previously reported and has the additional advantage that frequent sequential determinations of liver perfusion can be made.


Reversible functional asplenia in chronic aggressive hepatitis.

A 61-year-old man presented with aggressive hepatitis. Howell-Jolly bodies were present in circulating erythrocytes and the spleen failed to accumulate intravenously administered Tc-99 m sulfur colloid. The patient thus demonstrated functional asplenia. He was treated with high doses of steroids. Four years later, Howell-Jolly bodies were no longer present in circulating erythrocytes. In addition, the spleen had regained the ability to accumulate intravenously injected radiocolloid. Hence, the patient had reversed his functional asplenia. The reported cases of this disorder (reversible functional asplenia) were reviewed and a preliminary classification was proposed.


Complex formed from 3-hydroxy-4-formylpyridine, glutamic acid, and technetium--a possible cholescintigraphic agent.

In order to obtain a technetium-99m-labeled cholescintigraphic agent suitable for kit preparation, reactions of a variety of aromatic aldehydes, amino acids, and [99mTc] pertechnetate were examined under mild conditions. Aqueous solutions of the three reactants were heated in a boiling-water bath and the products analyzed by means of thin-layer chromatography for the formation of organic technetium complexes. 3-Hydroxy-4-formylpyridine (HFP) and 1-methyl-3-hydroxy-4-formylpyridinium chloride (N-Me-HFP) formed the complex with excellent yields, whereas 3-hydroxy-2-formylpyridine, 4-nitrosalicylaldehyde, salicylaldehyde, and isonicotinaldehyde did not. The complex is concluded to be the Tc-99m chelate of the Schiff base formed from the aldehyde and amino acbbits administered with the complex of HFP, glutamic acid and Tc-99m. The results indicate that it is promising as a cholescintigraphic agent.


Optimization of the gray scale for photoscanners: concise communication.

A gray scale providing easy visual interpretation of black-and-white photoscan transparencies was determined empirically from psychophysical studies conducted on 50 observers. This optimum gray scale provides equal visualization for equal countrate changes over the entire film range.


Pharmacokinetics of hepatobiliary imaging agents in rats: concise communication.

The distribution and elimination kinetics of Tc-99m pyridoxlidene glutamate (Tc-99m PG), of Tc-99m N-(2,6-dimethyl-phenylcarbamoylmethyl) iminodiacetic acid (Tc-99m HIDA), and of I-131 rose bengal in blood were quantitated after i.v. injection in rats. This was performed by use of a unique indwelling catheter that externalizes the systemic circulation, permitting continuous monitoring of blood radioactivity. The blood activity-time curves of Tc-99m PG and Tc-99m HIDA are described by the sum of three exponential functions. Only two exponentials are required in the case of I-131 rose bengal. The rank order for the rates of loss from blood was Tc-99m HIDA less than Tc-99m PG less than I-131 rose bengal. Bile was collected after administration of Tc-99m HIDA and Tc-99m PG. The total excretion of radioactivity over a 70-min period amounted to 95.7% and 42.8% of the dose of Tc-99m HIDA and Tc-99m PG, respectively. A linear compartmental kinetic model was developed to account for the disappearance from blood and the biliary excretion of these radiopharmaceuticals in rats.


Absorbed dose to the human adrenals from lodomethylnorcholesterol (I-131) "NP-59": concise communication.

During the past 2 years, adrenal uptake percentage values were measured in more than 40 patients, using an external counting technique. They suggest that the absorbed dose to the adrenals is significantly less than 150 rads/mCIi previously estimated using concentration values from animal adrenals. The measured combined uptake percentage for both adrenals ranged from 0.15% to 0.52% in 21 patients without evidence of adrenal disease, with a mean of 0.33% +/- 0.1%; also from 0.22% to 1.5% in 22 patients with Cushing's disease, with a mean uptake of 0.78% +/- 0.35%. The absorbed dose to the adrenals was estimated to be 25 rads/mCi for patients without evidence of adrenal disease, and 57 rads/mCi for patients with Cushing's disease. Both values are calculated for the respective mean uptake percentages by using MIRD formalism.


Adrenal imaging with iodomethyl-norcholesterol (I-131) in primary aldosteronism.

Twenty consecutive patients with primary aldosteronism (PAl) underwent dexamethasone suppression (DS) imaging with 6beta-[131I]-iodomethyl-19-norcholesterol (NP-59): A) to establish the value of the adrenal scan in distinguishing aldosteronomas from bilateral hyperplasia; b) to determine its ability to locate aldosteronomas when present; and c) to compare the efficacy of NP-59 in this current series against that reported previously with NM-145 in PAl. Ten of twenty patients had an aldosteronoma, five had histologically confirmed hyperplasia, and five had presumed hyperplasia. With NP-59, nine of ten tumors were correctly located (90%) , correct distinction between tumor and hyperplasia was possible in 90%, and a locating DS scan was specific for tumor in 90%. In a combined series of different patients with PAl imaged with NM-125, 21 of 25 tumors were correctly located (84%), tumor was distinguished from hyperplasia in 86%, and the specificity of the localizing scan was 92%. The imaging delay required from tracer injection to attainment of an interpretable scan averaged 2.7 days with NP-59 and 4.8 days with NM-145. In summary, no significant differences were noted in the clinical results achieved with these two agents. The preferred agent is NP-59, since the study can be completed with less average time delay than is possible with NM-145.


Assessment of serum myoglobin as a marker for acute myocardial infarction.

The reliability of serum myoglobin as a marker for acute myocardial infarction was evaluated in 157 consecutive coronary-care admissions. Admission myoglobin was elevated in 47 of 52 patients with acute infarction. Excluding those patients who presented later than 24 hr after symptom onset, only one patient with acute infarct had a normal admission myoglobin. In 22 of 105 patients with no infarct, myoglobin was elevated in association with angina, congestive heart failure, arrhythmias, and renal insufficiency. The detection of acute infarction by serum myoglobin measurement equals that of serial serum creatine phosphokinase isoenzymes (CPK-MB) by electrophoresis, but an elevated myoglobin is not specific for what is now considered clinically significant myocardial infarction.


Serum myoglobin determination: laboratory and clinical evaluation.

Quality assurance examination of a commercially available radioimmunoassay kit for determination of serum myoglobin level conformed the measurement to be accurate, precise, and reproducible under all assay performance variables. Initial clinical evaluation in patients admitted to the Coronary Care Unit revealed comparable diagnostic parameters and earlier detection when compared with the present standard indicator of myocardial necrosis, creatine phosphokinase MB isoenzyme. Interpretation that an elevated myoglobin reflects acute myocardial infarction should be made only in the appropriate clinical context.


Hypervascular presentation of multiple myeloma involving the skull, demonstrated on encephaloscintigraphy.

We present two cases of myelomatous involvement of the skull. Correlative studies with routine radiography, angiography, and encephaloscintigraphy were performed. The areas of involvement of the skull were confirmed as autopsy. A mixed pattern of photon-deficient and photon-abundant lesions was noted. The clinician should be aware of such mixed patterns.


Visualization of alcohol-induced rhabdomyolysis: a correlative radiotracer, histochemical, and electron-microscopic study.

Technetium-99m diphosphonate was used to visualize the extent of alcohol-induced rhabdomyolysis and its resolution. Transient secondary hyperparathyroidism was documented. Histological and biochemical analyses of skeletal muscle obtained at biopsy 6 days postscan and 9 days after the onset of the illness did not show abnormal calcium content.


Migratory osteolysis.

Migratory osteolysis is a recently recognized syndrome characterized by a migratory articular pain pattern of the lower extremities and associated radiographically with localized and reversible juxta-articular osteoporosis. Serial bone scans, both dynamic and static, appear to offer a new and more sensitive means for diagnosing and monitoring of this condition. The dynamic studies suggest that augmented osseous blood flow is responsible, at least in part, for increased radioactivity in clinically involved areas and presumably is mediating the osteoporotic process.


Colloidal particle-size determination by gel filtration.

The particle sizes of technetium-99m sulfur colloid and technetium-99m antimony sulfide colloid are determined by gel filtration. These results are compared with those obtained by electron microscopy and by ultrafiltration. It is shown that gel filtration is suitable for particle-size determination below 100 nm, whereas above this size ultrafiltration provides the most convenient method.


Imaging the adrenal medulla with an I-131-labeled antiadrenergic agent.

Tissue distributions of four antiadrenergic agents labeled with iodine-125 have been determined in dogs. [125I] ortho-iodobenzldimethyl-2-hydroxyethyl ammonium and [125I] ortho-iodobenzyldimethylethyl ammonium show highly selective uptake in the adrenal medulla. Studies of molecular structure-distribution indicate that both the nature of the cationic head and the ring position of the iodine atom greatly influence adrenal specificity. Distinct images of dogs' adrenal medulla have been obtained 4 days after i.v. injection of 1.5 mCi of [131I] ortho-iodobenzyldimethyl-2-hydroxyethyl ammonium.


A simple method for the air monitoring of xenon-133.

A simple and inexpensive method to monitor the air for Xe-133 is described. The procedure requires only standard 10-cc evaculated tubes, a scintillation well counter, and a dose calibrator--standard equipment in most nuclear medicine laboratories. Air contamination in the range of the maximum permissible concentration in restricted areas (10pCi/cc) can be detected easily by this technique.


Comments on equilibrium, transient equilibrium, and secular equilibrium in serial radioactive decay.

Equations describing serial radioactive decay are reviewed along with published descriptions of transient and secular equilibrium. It is shown that terms describing equilibrium are not used in the same way by various authors. Specific definitions are proposed; they suggest that secular equilibrium is a subset of transient equilibrium.


In vivo analysis of bone calcium by local neutron activation of the hand: results in normal and osteoporotic subjects.

Mineral loss from bone can be measured accurately and reproducibly by neutron activation of the hand bones using a 5-min irradiation (10(6) n/cm2-sec) with two 200-microgram sources of Cf-252. The hand dose is 7.5 rad equivalent and the dose to the rest of body is 1.5 mrem. Controls (132) and osteoporotic patients (45) were compared. Between ages 20 and 60 the control group showed a bone calcium concentration of 0.177 +/- 0.025 g/cm3, independent of age. Between 60 and 70 the content remained unchanged in men but declined in women to 0.15 +/- 0.2 g/cm3. In all age groups osteoporotic patients in general showed lower calcium content. Comparison of our findings ("Ca") with estimates of bone mineral content obtained by photon absorptiometry ("BMC") yields 0.07 Ca + 0.262 (r = 0.87). Activation analysis of hand bone appears more precise than BMC for the monitoring of bone-mineral loss in each individual and as a measure of treatment efficacy.


Comparison of the distribution of diagnostic and thyroablative I-131 in the evaluation of differentiated thyroid cancers.

In 206 patients with differentiated thyroid cancer, the distribution of iodine-131 were compared after diagnostic (200-500 microCi) and thyroblative (approximately 100 mCi) doses. In the diagnostic scans, only normal thyroid tissue could be seen, whereas in one-fourth of the patients the therapeutic scans showed tumor tissue as well, usually in lymphnode metastases. In 16% of patients, the therapeutic scan was the only way to demonstrate the presence of tumor tissue, since no further uptake was achievable. In patients in whom all tumor was believed to have been removed by surgery alone, a "preventive" I-131 ablation was used, and in 16 of these 97 patients tumor was revealed in the therapeutic scan. In ten more, tumor was found in subsequent followup scans, its functioning having been induced by destruction of postsurgical remnants of normal thyroid. Some possible explanations for the differences in scans are proposed, and the importance of therapeutic scans for correct staging of thyroid cancer is stressed.


A clinical comparison of Tc-99m HEDP and Tc-99m MDP in the detection of bone metastases: concise communication.

We have compared bone scintigrams made with Tc-99m-tagged HEDP (1-hydroxyethylidene diphosphonate)and MDP (methylene diphosphonate), the former at 4 hr after injection, the latter at both 2 and 4 hr. In 17 patients with skeletal metastases, there was no significant difference in lesion count or scan quality between the 4-hr images. The tumor-to-bone ratio (T/B) was significantly higher with Tc-HEDP (p less than 0.02). Lesion detection rate and T/B ratios were both lower with Tc-MDP at 2 hr when compared with the 4-hr values for both Tc-HEDP (p less than 0.02, p less than 0.005) and Tc-MDP (p less than 0.02, p less than 0.01). The 4-hr Tc-MDP scan was of significantly higher quality than the 2 hr Tc-MDP scan (p less than 0.01). Although Tc-HEDP produces a higher T/B ratio at 4 hr, the present study does not suggest that either agent is superior in clinical practice.


Availability of adipose tissue tocopherol in the guinea pig.

Young guinea pigs were fed a purified diet containing vitamin E for 3 weeks and then fed the diet without vitamin E for 8 weeks. Levels of vitamin E in plasma and liver decreased to low values within a week. Depletion rates for heart and muscle were much slower, whereas the rate of loss from fat was negligible. In experiments with more mature guinea pigs and a depletion period of 4 months, the depletion rate of tocopherol from fat was also barely detectable. Both yound and mature guinea pigs developed myopathy after 8 weeks of depletion. Apparently, tocopherol in adipose tissue is not sufficiently available to maintain plasma tocopherol levels or to prevent signs of vitamin E deficiency. Even during fasting, adipose tissue tocopherol was not mobilized readily. During a 4 day fast, adipose tissue mass diminished considerably, but there was no appreciable loss of tocopherol.


In vitro studies of fatty acid metabolism in vitamin B6 deficient rats.

The oxidation of [1-14C]palmitate, [1-14C]linoleate, and [1-14C]arachidonate as well as their incorporation into lipids was investigated in vitamin B6 deficient rats using liver slices and isolated mitochondria. In experiments on fatty acid oxidation in liver slices, we observed a decrease in the production of 14CO2 from radioactive palmitate and linoleate, but not from arachidonate. In the case of mitochondria, we detected no difference between the deficient rats and the controls with linoleats; however, there was an increase in the oxidation of palmitate in the deficient rats as compared to the controls. Experiments on the incorporation of radioactivity into lipids showed an increase in radioactivity from [1-14C]palmitate and [1-14C]linoleate in the triglyceride, phospholipid and cholesterol fractions of deficient rats. In the case of [1-14C]arachidonate, no difference was observed between the two groups of rats. These experiments showed that major changes occurred in metabolism of palmitate and linoleate and strongly suggested that the decrease in the arachidonate content previously observed in rat tissues could not be explained by alteration in the metabolism of this fatty acid.


Determination of the site of zinc absorption in rat small intestine.

We have studied net uptake of zinc from segments of rat duodenum, jejunum, and ileum using in vivo intestinal perfusion. We have also evaluated the effect of pancreatic and bile secretions on duodenal zinc absorption. Segments of duodenum, jejunum, and ileum and duodenum with bile and pancreatic duct obstruction, 10 cm in length, were studied in six rats each. Percentage absorption of zinc as determined by atomic absorption spectrophotomety was greater from the ileum (60.1%) when compared to duodenum (19.1%) or jejunum (20.2%). Exclusion of bile and pancreatic secretions from the lumen increased zinc absorption in the duodenum (32.0%). Postperfusion mucosal zinc content comprised 29.0% of absorbed zinc from jejunum, 7.4% from ileum, 5.2% from duodenum, and 2.7% from duodenum with bile and pancreatic duct obstructed, indicating rapid transport of zinc across epithelial cells after uptake from the duodenum and ileum. Our data indicate that the ileum has the greatest capacity for zinc absorption.


The effect of long-term fasting on the branched chain acylcarnitines and branched chain carnitine acyltransferases.

The effect of fasting for 8 days on the levels of carnitine acyltransferases in heart, liver, liver mitochondria, skeletal muscle, skeletal muscle mitochondria, kidney, and testes in young adult male rats was determined. The specific activities of acetyl-, octanyl-, isobutyryl-, and isovaleryl-carnitine acyltransferase in mitochondria isolated from the livers of fasted animals were significantly higher than the levels of the transferases isolated from livers of fed animals. Similar results were obtained with the 500 x g supernatant fluids from liver. In contrast, the specific activities of carnitine acyltransferases of 500 x g supernatant fractions isolated from heart, skeletal muscle, kidney, and testes were the same for fed as fasted animals. The total carnitine content of liver, muscle, heart, and kidney was less in animals fasted for 8 days than in fed animals, but the amount/g of organ was higher in the animals fasted for 8 days. The amount of specific short-chain acylcarnitines in liver, muscle, and heart was determined for both fed and fasted animals. The amount of isobutyrylcarnitine and isovalerylcarnitine increased significantly in muscle from fasted animals. These data are consistent with the previous suggestion that carnitine may have a role in the metabolism of the branched-chain amino acids.


Interrelationships in rats among dietary vitamin B6, glycine and hydroxyproline. Effects of oxalate, glyoxylate, glycolate, and glycine on liver enzymes.

Urinary endogenous oxalate was increased by feeding vitamin B6-deficient or control rats with 5.2% hydroxyproline, or 3% glycine plus 5.2% hydroxyproline. The activities of liver lactic dehydrogenase (LDH), glucose-6-phosphate dehydrogenase (G6PD) , malic enzyme (ME), and ATP citrate lyase were decreased in vitamin B6-DEFICIENT RATS, AND THEIR LIVEr G6PD was further decreased by the addition of glycine and hydroxyproline to their diets. Supplementing control diets with the two amino acids decreased the activities of rat liver LDH, G6PD, and ATP citrate lyase. The effects of glycine and hydroxyproline feeding on the enzymes studied did not appear related to alterations in insulin availability. Since in vitamin B6-deficient rats, there are increases in urinary levels of oxalic and glycolic acids, and glycine, and increases in tissue levels of glyoxylic acid and glycine, the effects of these metabolites on the activities of the above mentioned enzymes were measured. Oxalic acid inhibited the activities of LDH, G6PD, and ME. Glyoxylic acid inhibited LDH and ME, but not G6PD. Glycolic acid inhibited G6PD and ME, but not LDH. ATP citrate lyase was not affected by these substances. Glycine had no effect on the enzymes studied. Diets which increased oxalate excretion generally reduced or did not alter liver and kidney levels of oxalate, glycolate, and glyoxylate. However, the feeding of glycine and hydroxyproline increased kidney oxalate, and liver and kidney glyoxylate in vitamin B6-deficient rats.


Thymidine kinase and DNA polymerase activity during postnatal growth of the epididymal fat pad.

Thymidine kinase and DNA polymerase enzyme activities were measured in epididymal adipose tissue from rats of 12 to 182 days of age. Both enzymes showed highest specific activity during the suckling period; by 35 days of age both thymidine kinase and DNA polymerase enzyme activities had decreased to stable lower levels. The activities of the two proliferative enzymes resembled the pattern of [3H]thymidine incorporation into preadipocytes shown by Greenwood and Hirsch (1) and the data support the concept that a pool of preadipocytes develops during the first 4 to 5 weeks postnatally. Further, the thymidine kinase and DNA polymerase enzyme activities were correlated with the rate of DNA accretion in the preadipocyte fraction of the tissue. Since thymidine kinase activity can be measured in 20 to 40 mg of tissue. Since thymidine kinase activity can be measured in 20 to 40 mg of tissue, the technique can be adapted for measurement of enzyme levels in human or animal biopsy samples when radio-isotope studies are not advisable or only small quantities of tissue are available.


Studies on the ameliorating effect of ascorbic acid on mineral toxicities in the chick.

The effect of dietary ascorbic acid on the toxicity of high levels of cobalt, selenium, vanadium, cadmium, copper, and mercury was determined in chicks. The vitamin reduced the growth retardation caused by cobalt, selenium, vanadium, and cadmium administration but had no such effect on copper and mercury toxicity at the levels used. The effect of ascorbic acid on growth could not be mimicked by ferrous iron administration. Ascorbic acid did not alleviate the increased susceptibility of chicks to Salmonella gallinarum caused by feeding high levels of these elements.


Protein evaluation in growing rats of breast milk and breast milk substitutes with special reference to the content of non-protein nitrogen.

The levels of individual proteins and other nitrogen containing substances differ considerably between cow's milk and human milk. Therefore, during manufacture of infant formulas, attempts are made to simulate the protein composition of human milk. However, the composition and nutritional characteristics of human milk protein are incompletely known. In this paper, the protein quality of breast milk protein with and without the non-protein-nitrogen (NPN) substances present in human milk was studied with growing rats and compared to two formulas, one "adapted" commercial infant formula and a suggested further modified, possibly improved, infant formula. Detailed examinations of protein and amino acid composition of the test diets are given. Breast milk protein with added NPN substances showed a lower protein quality than all other test proteins. Breast milk protein without NPN substances and the protein of the suggested infant formula were of similar quality while the protein of the commercial adapted formula was significantly better than all other test proteins. The use of rat growth assays in the evaluation of protein quality of infant formulas is discussed.


Lipid composition of liver plasma membranes isolated from rats fed a high glucose or a high fat diet.

Several plasma membrane associated functions have been shown to differ in rats fed a high lard, carbohydrate free diet (L rats) from those observed in preparations from rats fed a high glucose, fat free diet (G rats). To explore the possibility that differences in the lipid components of the plasma membranes might contribute to these functional changes, groups of rats were fed each diet for 5 days and the lipids of their plasma membranes were separated and analyzed. The major differences found were a greater cholesterol content in the plasma membranes from L rats compared to those of G rats (12.2 +/- 2.20 versus 7.8 +/- 1.40 mg/100 mg membrane protein) and more than twice as much phosphatidyl serine and phosphadidyl inositol in the plasma membranes of the former group. Of several variations in fatty acid distribution found in the phospholipid and neutral lipid fractions, the most notable quantitatively were an increase in phospholipid oleic acid (18:1) and a decrease in phospholipid stearic acid (18:0) in L rat plasma membranes. Whether these changes are related to altered membrane function is not known.


Growth, lipid metabolism and pathology of two strains of rats fed high fat diets.

Studies were carried out on Sprague-Dawley (SD) and Chester Beatty (CB) rats to determine whether the difference in incidence of myocardial lesions can be related to dietary factors and parameters known to be affected in SD rats fed rapeseed oils. The two strains of young, male rats were fed diets which contained 20% by weight of either corn, LEAR (low erucic acid) or HEAR (high erucic acid rapeseed) oils for a period of up to 16 weeks. A significantly lower incidence of focal myocardial necrosis was observed in CB rats than in SD rats. The incidence of this heart lesion in CB rats was similar between all diets; in SD rats a higher incidence was observed in the groups fed rapeseed oils. In both strains the growth rates of rats fed LEAR and corn oils were similar; growth rates with HEAR oil diets were much lower than the other oils. Severe myocardial lipidosis was only evident in rats fed HEAR oil, but no strain differences were observed. The pattern and extent of lipidosis, including cardiac and hepatic lipid levels and fatty acid compositions, were similar in both strains at the time periods studied. Cardiac triglycerides and free fatty acids increased in rats fed HEAR oil, but no strain differences were evident. Strain differences were found in the levels of a few cardiac phospholipids of rats fed HEAR oil, however, the relative fatty acid compositions of each phospholipid were remarkably similar. Microscopic examination of the livers showed no evidence that feeding rapeseed oil caused any specific effect which could be related to differences in heart lesion response. There was no evidence to indicate that differences in heart lesion response between the two rat strains could be related to cardiac triglycerides, free fatty acids or phospholipids.


Studies on the control of lipogenesis: strain differences in hepatic metabolism.

Detailed studies of hepatic metabolism of lipemic BHE and nonlipemic Wistar rats were conducted. Hepatic lipogenic capacity was varied through the use of starvation or meal feeding. Livers were clamped in precooled copper plates and used for the assay of glycolytic, gluconeogenic, and lipogenic metabolites. Redox and phosphorylation states were calculated. Mitochondrial metabolism was evaluated through studies of the oxygen consumption of isolated mitochondria and through the study of the activities of the alpha-glycerophosphate and malate aspartate shuttles and ATPase. BHE rats have higher phosphorylation states, higher redox ratios, and lower shuttle activities and oxygen consumption by isolated mitochondria than their Wistar cohorts. The differences in oxidative phosphorylation, redox and phosphorylation states, and in the various shuttle activities suggest that BHE liver cells are geared towards lipogenesis at the expense of oxidative phosphorylation. It appears that the activity of the shuttles is controlled in part by phosphorylation state which in turn appears to affect respiration. We theorize from these data that genetically determined differences in the structure and function of the mitochondrial membrane (and perhaps the cell membrane as well) may affect the communication (via metabolites and adenine nucleotides) between the cytosol and mitochondria. Subtle differences in the exchange of metabolites and/or adenine nucleotides across the mitochondrial membrane could thus explain the lipogenic tendency of the liver of the BHE rat and the subsequent development of maturity onset hyperlipemia and hyperglycemia in this strain of rat.


Effects of age, strain, and dietary carbohydrate on the hepatic metabolism of male rats.

The effects of age and the duration of feeding either a 65% sucrose or a 65% starch diet to normolipemic Wistar and potentially hyperlipemic-hyperglycemic BHE male rats on hepatic metabolite levels, calculated redox and phosphorylation states were studied. Consistent with previous reports, the feeding of sucrose to BHE rats hastened the appearance of hyperlipemia while having little effect in Wistar rats. The changes in hepatic metabolites were consistent with an increased hepatic lipogenesis in BHE rats. The results suggest that the effects of feeding sucrose to BHE rats potentiate the genetically increased hepatic lipogenesis in these rats.


Effect of sex on the strain differences in hepatic metabolism of starved and nonstarved rats.

The hepatic metabolism of starved and nonstarved male and female rats from the Wistar and BHE (line 4) strains has been studied. Liver tissue was frozen between precooled copper plates and the levels of various metabolites of the glycolytic and citric acid cycle and adenine nucleotides determined. While the major differences in hepatic metabolism were attributable to the strain of animal, sex effects were also observed. These results suggest that differences in compartmental phosphorylation states may be indicative of a greater lipogenic capacity of these rats compared to normal rats.


Diet and glucose induced changes in rat duodenal and pancreatic serotonin and plasma glucose levels.

Serotonin concentrations in the duodenum and pancreas of rats fed 9, 22 (control), and 45% protein diets for 21 days were analyzed 15 minutes before (fasting levels) and 45 minutes after an oral glucose load. Fasting levels of serotonin were significantly higher in the duodenum of rats consuming the low and high protein diets. Plasma glucose levels were significantly higher in fasted rats receiving the low protein diet. Glucose load caused a significant decrease in duodenal concentration of serotonin and an increase in pancreatic serotonin among rats fed all three diets. The results suggest that duodenal serotonin levels change in response to diet composition whereas pancreatic serotonin is altered by glucose load.


Induction of threonine imbalance by dispensable amino acids: relation to competition for amino acid transport into brain.

The ability of low protein diets containing small neutral, dispensable amino acids to induce threonine imbalance has been examined. Diets containing amino acids which compete for threonine transport in vitro (serine, alanine, alpha-amino-n-butyrate) caused depressions of growth and food intake which could be corrected to varying degrees by adding threonine to the diet. Large neutral, indispensable amino acids, moderately inhibitory of threonine transport, also induced the imbalance. Some amino acids that had little or no effect on threonine transport in vitro (acidic amino acids and proline) did not cause growth and food intake depressions. Other non-inhibitory amino acids (arginine and lysine) caused growth depressions which were not satisfactorily corrected by additional threonine alone, but were prevented by supplements of all the indispensable amino acids including threonine. Ornithine which was also not inhibitory of threonine transport was an exception. It induced a moderate growth depression which was corrected by additional threonine. Similar studies showed that histidine or tryptophan imbalance could be induced by feeding diets containing only those large neutral amino acids which compete for histidine or tryptophan transport in vitro. These experiments show that, based on the results of transport competition experiments, it is generally possible to devise amino acid supplements which can induce a dietary imbalance of a given amino acid.


Response of submandibular gland of the rat to nutritional zinc deficiency.

Studies in several laboratories have shown that nutritional Zn deficiency in the rat causes a reduction in the activity of certain Zn-dependent enzymes in kidney, intestine, pancreas, etc. The present report deals with the effects of Zn-deficiency on submandibular gland of the rat. For the sake of comparison with previous studies, some assays on pancreas were included. Protein content, DNA, acid phosphatase, and acid protease activities were not affected in submandibular gland. Lactate dehydrogenase was unaffected in submandibular gland and showed increased activity in pancreas. Malate dehydrogenase was significantly decreased in both organs, the decrease being more marked in submandibular gland. Alkaline phosphatase activity in submandibular glands of control rats was about 10-fold higher than in pancreas. In the zinc-deficient rats, alkaline phosphatase was reduced to 59% of controls in the submandibular glands and to about 75% in pancreas. It is known from histochemical studies that in the submandibular gland this enzyme is confined to the myoepithelial cells. Recent studies attribute to salivary glands a role in the etiology of taste disturbances seen in clinical states of zinc deficiency. It is proposed that functional impairment of the myoepithelial cells might contribute to the disturbance of taste.


Effect of vitamin B-6 deficiency on preference for several taste solutions in the rat.

The effect of dietary-induced vitamin B-6 (B-6) deficiency on the intake of the taste solutions, sodium chloride (NaCl), sodium saccharin (NaSacc), quinine sulfate (QS), and hydrochloric acid (HCl) was studied using a 48 hour, two-bottle choice technique. The B-6 deficient group demonstrated increased preference to 1.5 X 10(-1) and 3.0 X 10(-1) M NaCl compared to control ad libitum fed and control pair-fed groups. Total fluid intake on NaCl test days was also elevated in the B-6 deficient rats. There was no significant difference in the mean preference to NaSacc, QS, or HCl among the three groups. Adrenal hypertrophy was observed in the deficient rats. There was no change in the plasma level of Na and Zn but there was a reduction in urinary Na excretion. When the deficient rats were replenished by intraperitoneal injection of pyridoxine.HCl and feeding with the control diet containing adequate B-6, the increased preference for NaCl was extinguished, suggesting that the preference alteration was reversible. Urinary Na excretion also returned to normal.


Nitrogen balance studies in humans: long-term effect of high nitrogen intake on nitrogen accretion.

Six healthy young adult male participants were confined to a metabolic ward for 105 days. Two nutritionally adequate purified diets providing 12 and 36 g of nitrogen per day were randomized in two metabolic periods of approximately 50 days each. The objective of this study was to verify whether or not positive nitrogen balance is a concomitant of increased nitrogen intake under the most rigorously controlled conditions, and if so, whether adaptation could occur if the experiment was conducted for sufficiently long periods of time. The mean nitrogen balance was slightly negative for most participants when fed the 12 g N diet. However, individual variability was so large that statistically all the participants can be considered in balance. In view of this, we agree with other investigators who have suggested that balance should be considered as an area which takes into account variabilities such as intake, output and biological factors. On the 36 g N diet, all the participants exhibited strong positive balances, about 1.6 g/day, which were not as high as reported by other investigators but which persisted for as long as they were fed this diet. This positive balance could not seem to be explained on the basis of methodological errors or to any unmeasured nitrogen losses. There was no significant trend towards adaptation as claimed.


Effects of high and low erucic acid rapeseed oils on energy metabolism and mitochondrial function of the chick.

Duplicate experiments were conducted to compare energy utilization, growth, cardiac mitochondrial oxidative phosphoryl,tion, and mitochondrial membrane fatty acid composition of chicks fed diets containing 20 parts of high erucic acid rapeseed oil (HER), low erucic acid rapeseed oil (LER) or sunflower seed oil (SFO) for 24 days. Chicks fed diets containing HER deposited less fat and utilized energy less efficiently (kcal gained/kcal consumed) than chicks fed diets containing either LER or SFO. Energetic efficiency and fat deposition of chicks pair-fed diets containing LER were significantly lower than for chicks fed diets containing SFO. Cardiac mitochondria isolated from chicks fed diets containing either HER or LER for 24 days had significantly reduced ADP/O ratios and reduced rates of ATP synthesis utilizing pyruvate and malate as the respiratory substrates when compared with mitochondria isolated from chicks fed SFO. Diet induced transitions in fatty acid composition of cardiac mitochondrial membranes were also observed. The composition of fat ingested affected the fatty acid composition of mitochondrial diphosphatidyl glycerol more than the fatty acid composition of phosphatidyl choline or phosphatidyl ethanolamine. The linoleic acid content of mitochondrial diphosphatidyl glycerol was lower and the gadoleic acid and erucic acid content higher for chicks fed diets containing rapeseed oils than for chicks fed SFO containing diets. These studies indicate that a complex dynamic mechanism exists associating dietary fat with mitochondrial structural-functional changes and energetic efficiency in the growing chick.


Correlation between the physical properties of dietary fibers and their protective activity against amaranth toxicity in rats.

The mechanism(s) by which dietary fiber (DF) exerts beneficial effects on the growth of weanling rats fed toxic doses of amaranth (Food & C Red No. 2) was investigated. When crude DF (GDF) prepared from the roots of edible burdock (Arctium lappa L.) were added at graded levels to a purified basal diet supplemented with amaranth (control), growth was improved with increaseing GDF level up to and above that of the basal diet-fed group. The correlation equation obtained between the dietary percentage level of GDF (X) and the protective activity (Y) expressed as (difference in body weight gains between rats fed test and control diets) X 100/(difference in body weight gains between rats fed basal and control diets) was Y = 32.6 + 86.9 logX (r = 0.98). The comparative activities at the 5% level of various DF prepared from GDF decreased in the order of holocellulose, neutral-detergent fiber, GDF, crude fiber and acid-detergent fiber. Cellulose from cotton fiber had no activity. The activity was intimately related to their water-holding capacity (WHC) and settling volume in water (SV) (f = 0.90 and 0.96, respectively), but not to the capacity to bind amaranth. The correlation showed a saturation phenomenon quite similar to the equation described above in respect of GDF level. At the 10% level, even cellulose which has a low SV, showed protective activity similar to that of 3% GDF. From these and other results, it was concluded that the protective activity of various DF mainly depends on their physical properties such as SV or WHC.


Effect of zinc status on salivary zinc concentrations in the rat.

Three experiments were done to determine whether salivary zinc concentration is a more sensitive indicator of zinc status than plasma zinc. Weanling male rats fed a low zinc (less than 1 ppm) diet for 5 weeks with or without zinc (100 ppm) in the drinking water had salivary zinc concentration of 0.19, 0.16, and 0.20 microgram/ml for the zinc-deficient, zinc-supplemented restricted-intake, and zinc-supplemented ad libitum-fed groups, respectively. Combined values for male and female rats after 4 weeks of the same treatments in experiment 2 were 0.60, 1.2 and 0.44 microgram/ml. Saliva collected on day 22 of pregnancy contained 0.30 and 0.24 microgram/ml from zinc-supplemented and zinc-deficient rats, respectively. Salivary zinc concentrations in the deficient rats did not differ from those of the zinc-supplemented ad libitum-fed controls in any of the experiments. Salivary zinc concentration in the zinc-supplemented restricted-intake group in experiment 2 was significantly higher than that in the other two groups. Decreases in serum, bone, and fetal zinc concentrations indicated that the rats were definitely zinc-deficient. Since zinc concentration of mixed saliva in the rat was not decreased by even a severe zinc deficiency, salivary zinc does not appear to be as good an indicator of zinc status as plasma zinc.


An unrecognized dietary factor for guinea pigs associated with the fibrous fractions of plant products.

The growth rate of guinea pigs was used to assess the nutritional value of plant materials and to characterize the active component(s). Weanlings were fed for 28 days a purified diet based on soybean protein. Addition of 10 to 20% of wood pulp improved the growth rate beyond that supported by 0 to 5%. Subsequently, the basal diet contained 15% of wood cellulose. Raw cabbage, ad libitum, 5% of wheat straw and 5% of mature alfalfa, collected and dried in the laboratory, increased growth rate significantly. Several other plant products tested were inactive. Holocellulose (2.5%) prepared from alfalfa improved the growth rate while that from cabbage was minimally active. Afalfa holocellulose fractions enriched in hemicellulose and alpha-cellulose were inactive. Lyophilized cabbage and the residue which remained after extraction of frozen raw cabbage with ethyl acetate and acetone stimulated growth when fed at a level of 10%. Treatment of holocellulose with KOH, with pancreatin at pH 8 or with 0.1 m KHCO3 caused loss of activity. Storage of dry alfalfa meal for a period of 1 year resulted in loss of activity. It is concluded that a labile component of alfalfa associated with the fibrous fraction confers unique nutritional value to the fiber. Cabbage also contains a labile growth stimulant which may be associated with the fibrous fraction.


Growth of body protein, fat, and skeleton in steers fed on three planes of nutrition.

The growth of body protein, fat, and skeleton of growing steers was determined from published experimental data of steers fed three planes of nutrition. Each animal was partitioned into: 1) metabolically slow tissue which included hide, hooves, horns, skeleton, and fat, and 2) metabolically active tissue (MAT) which were the remaining tissues. MAT grew exponentially in time and approached the same final value for all planes of nutrition; however, growth rates depended on energy intake. The mass of active tissues was described by MATkg = 27 + 393 (1 - e-t/tau) where t and tau are in months; tau was 25.8, 46.7, and 57.4 months for the high, medium, and low planes of nutrition, respectively. The finding that MAT retained the same mathematical form but grew more slowly on the lower nutritional planes suggests that changes in energy set the scale of physiological age. Fat deposition was linear with time for all groups, although the rates depended on energy intake. The rates were 8.21, 2.08, and 1.29 kg/month for the high, mediu, and low planes of nutrition, respectively. The results suggest that steers are not programmed to synthesize protein first and then fat only with the remaining energy; rather the level of energy intake and the age determine how the ingested energy is partitioned into protein and fat synthesis.


Cadmium and the food chain: the effect of dietary cadmium on tissue composition in chicks and laying hens.

The cadmium content of body tissues and eggs was studied in broiler chicks and laying hens fed diets supplemented with 3, 12, and 48 microgram/g of cadmium. The 48 microgram/g level was selected as a slightly toxic level while the lower levels were felt to be representative of the amounts of cadmium which would occur in feedstuffs due to environmental contamination. All levels of cadmium resulted in increased cadmium content of kidney while only 12 and 48 microgram/g resulted in increases in the cadmium content of liver and muscle. As little as 3 microgram/g cadmium consistently increased the cadmium content of liver and muscle but this did not prove to be statistically significant. The transfer of dietary cadmium to the egg was found to be very low. Only the 48 microgram/g level resulted in an increase in cadmium content of the egg. This dietary treatment also resulted in reduced egg production and egg shell thickness.


Glutathione peroxidase acitvity in intestinal and liver tissues of rats fed various levels of selenium, sulfur and alpha-tocopherol.

The effects of various levels of selenium, alpha-tocopherol and sulfur on glutathione peroxidase (GSH-Px) activity in intestinal and liver tissues were determined in male rats fed corn-soybean or Torula yeast diets. Rats fed corn-soybean diets had greater GSH-Px activity in the small intestine, colon and liver tissues, catalase activity and selenium in the liver, and body weight gains than those fed Torula yeast diets. GSH-Px activity in the small intestine, colon, and liver tissues as well as concentration of selenium in the liver increased with increasing levels of selenium in Torula yeast diets but not with corn-soybean diets. Tocopherol supplementation had no significant effect on GSH-Px activity in rats fed Torula yeast or corn-soybean diets supplemented with selenium. Supplemental sulfur decreased GSH-Px activity in the small intestine tissues and increased activity in colon tissues.


Preventive effects of phylloquinone on hemorrhagic death induced by butylated hydroxytoluene in male rats.

The effects of vitamin K on hemorrhagic death induced by dietary butylated hydroxytoluene (BHT) were studied. Male Sprague-Dawley rats were given BHT or two phenolic antioxidants (2,4,6-tri-tert-butylphenol and 2,5-di-tert-butylhydroquinone) in combination with a 24% casein basal diet. The levels of the phenols were chosen to nearly equal LD50 (40 days). Hemorrhagic death, hemorrhage and a decrease in prothrombin index caused by 1.20% BHT were prevented by simultaneously adding phylloquinone (0.68 mumole/kg/day). Phylloquinone also inhibited the effect of the related phenolic antioxidants. Ten nanomoles of phylloquinone injected into the femoral vein on day 3 of feeding 1.2% BHT increased the prothrombin concentration from 28% of normal to 100% of normal within 18 to 24 hours. Phylloquinone oxide also prevented hypoprothrombinemia due to BHT. These results suggest that BHT-induced hemorrhagic death may be caused by direct and/or indirect vitamin K deficiency, and its mechanism may be different from those of warfarin.


The preferential transport of immunoglobulin G by the small intestine of the neonatal piglet.

Previous work dealing with the acquisition of passive immunity by the neonatal mammal has shown that the piglet is qualitatively nonselective with regard to the transport of macromolecules from the gut to the blood, whereas rats, mice and hamsters transport only immunoglobulin G (IgG) in detectable quantities. The ability of enterocytes of the proximal and distal small intestine of piglets to internalize fluorescent porcine IgG, bovine albumin or a mixture of these two fluorescent proteins was assessed. At the light microscopic level (macropinocytosis) porcine IgG and bovine albumin were internalized with equal facility by these enterocytes. To determine whether piglets preferentially transported porcine IgG versus bovine albumin, other piglets were gavaged with these proteins or these proteins were injected into ligated segments of the proximal or distal small intestine. Enterocytes in the proximal part of the small intestine transported more of these proteins (P less than 0.10) than did those in the distal part. When either bovine albumin or porcine IgG was presented separately to the piglet's gut, both were transported to about the same low level. However, when mixtures of these proteins were presented, IgG was preferentially transported, i.e., albumin enhanced IgG transport. Porcine albumin or polyvinylpyrrolidone (PVP) also enhanced porcine IgG transport. It was proposed that the preferential transport of IgG occurred by a micropinocytotic mechanism (not visible by light microscopy) and that other macromolecules such as albumin and PVP enhanced IgG transport by nonspecifically stimulating micropinocytosis.


Effect of glucocorticoids and zinc deficiency on femur and liver zinc in rats.

Male weanling rats were fed diets containing less than 1, 3, 6 oor 13 ppm zinc or stock rat diet for 3 weeks. Each dietary group was subdivided into a control group and a prednisolone-treated group (5 mg pred/kg body weight). Femur and liver zinc contents were determined by flame atomic absorption spectrophotometry. Prednisolone caused growth retardation at all levels of dietary zinc. A marked increase was seen in femur zinc content of prednisolone-treated rats fed zinc-deficient diets. No such increase was seen in rats fed diets adequate in zinc. No significant change was seen in liver zinc content of zinc-deficient rats due to prednisolone. By comparing femur zinc in rats fed zinc-deficient diets with femur zinc in weanling rats, it appears that prednisolone causes an increase in femur zinc in rats fed deficient diets by (a) preventing bone resorption, and (b) increasing femur uptake of dietary zinc. Because the effects of glucocorticoids in rats appear to differ from effects in man, similar studies in other species are recommended.


Effect of feeding 1,3-butanediol-1,3-dioctanoate as an energy source for chicks for catch-up growth during recovery from Newcastle disease virus.

1,3-Butanediol-1,3-dioctanoate (BDDO), a synthetic source of energy, has been shown to be equal to corn oil when fed to chicks recovering from moderate and severe Newcastle disease virus infections. Body weight increments of chicks fed diets containing 10% BDDO were equal to or greater than those of chicks fed 10% corn oil, both with restricted feeding regimens. Kilocalories of metabolizable energy required to produce 100 g of body weight increment over a basal group was used as a means of quantitating energy demand. BDDO was comparable to corn oil as an energy source with no adverse effects. Liver/body weight ratios were greater in the BDDO-fed chicks. Circadian rhythmicity of liver size and liver glycogen content was demonstrated. Chicks fed BDDO had total liver glycogen content threefold that of the corn oil controls, which was attributed to stimulation of insulin secretion. Catch-up growth in the chick following the growth depression of disease appears to be as well facilitated by a synthetic source as by a natural one.


Interaction of zinc and essential fatty acids in the rat.

Three experiments were performed to investigate the possibility of a physiological relationship between zinc and essential fatty acids (EFA). Male weanling rats were fed diets low in zinc, EFA or both and their growth rates, dermal scores and tissue fatty acid profiles determined. In experiment 1, a basal soybean protein diet containing 7 ppm of added zinc and approximately 300 ppm EFA was used in a 2 X 2 factorial design: low Zn-low EFA; adequate Zn-low EFA; low Zn-adequate EFA and adequate Zn-adequate EFA. The low zinc status accentuated signs of EFA deficiency, including dermal lesions and growth rate, but it had no significant effect on the fatty acid profile in plasma. In experiment 2, a basal casein diet containing approximately 25 ppm of EFA and less than 1 ppm of zinc, was used in a similar design. For 7 weeks two groups of weanling rats were fed ad libitum either a diet adequate in Zn and low in EFA or a diet adequate in all nutrients. From 7 to 12 weeks zinc was removed from one-half of each group and all were pair-fed to the intake of the low zinc-low EFA group. Zinc deficiency accentuated dermal lesions in the group deprived of EFA and caused enlarged joints suggestive of an arthritic-like syndrome. In experiment 3, an egg albumin based diet containing approximately 25 ppm EFA and less than 1 ppm of zinc was used in a 2 X 2 factorial design. No signs of fatty acid deficiency occurred in 5 weeks with adequate zinc. Zinc and EFA deficiency accentuated dermal scores and severely depressed growth. Zinc deficiency increased the proportion of arachidonic acid in foot skin especially in the EFA deficient group. It is concluded that there is a physiological interaction between Zn and essential fatty acids.


Inhibitory effect of dietary arginine on growth of Ehrlich ascites tumor cells in mice.

The effect of dietary L-arginine on the growth and development of transplantable Ehrlich Ascites tumor cells was examined. Growth of tumor bearing mice was significantly inhibited by feeding a purified casein diet supplemented with 5% arginine. This diet significantly reduced the total number of free tumor cells growing in the peritoneal cavity of mice. Total free tumor cell RNA, DNA, and protein were also significantly reduced. Supplemental arginine approximately doubled the length of time for 50% death of tumor bearing mice. Arginine did not alter respiration as measured by glucose or citrate oxidation. Varying the concentration of supplemental dietary arginine revealed that 3% arginine also significantly retarded the growth of Ehrlich Ascites Tumor Cells. Tumor ornithine decarboxylase activities were significantly reduced by dietary arginine supplementation. Supplemental dietary arginine at 3 or 5% did not significantly affect the growth of non-tumor bearing mice. Dietary arginine may play a critical role in growth of normal as well as neoplastic tissue.


Body weight and depot fat changes as influenced by exercise and dietary fat sources in adult BHE rats.

Adult male BHE rats were fed diets containing 15% of either corn oil (CO) or medium chain triglycerides (MCT) as the dietary source of fat. Further, rats were allowed to remain sedentary or were forced to exercise by swimming for 1 hour daily, for 3 weeks, followed by swimming for 2 hours daily for 3 weeks. The exercise for 3 weeks caused significant reductions in average body weight gains. After 6 weeks of exercise the lipid content of the adipose cells was reduced by about 50%. Fat cell numbers were not changed by either fat source or exercise, but fat cell size was significantly reduced after swimming daily for 6 weeks.


The effect of dietary protein levels on mineral toxicity in chicks.

Studies have been conducted to determine the influence of dietary protein levels of 10, 20, and 30% fed as soybean meal on the toxicity of selenium, cadmium, vanadium, cobalt, and nickel to chicks. The toxicity was evaluated in terms of growth retardation and a decrease in resistance to S. gallinarum infection as measured by mortality. The toxicity of selenium or cadmium was unaffected by the protein level of the diet while the toxicity of vanadium, cobalt and nickel was decreased by increased dietary protein as measured by the interactions on growth. The interactions apparent on growth were not as apparent on resistance to infection indicating that the latter parameter is much less sensitive to these dietary manipulations than is growth.


Effect of lactose on duodenal calcium-binding protein and calcium absorption.

Rats were fed a purified diet containing 30% lactose and calcium absorption was measured in duodenal loops in situ following instillation of 1.25 or 10 mM CaCl2 solutions. Lactose feeding caused absorption to be depressed from 88 to 69% (1.25 mM Ca solution) and from 71 to 43% (10 mM Ca solution). The effect of lactose feeding was more pronounced in 5-month old rats than in 2-month old rats. In the lactose-fed rats, calcium-binding protein (CaBP), measured by a competitive binding assay following partial purification, was depressed on the average from 24 to 10 nmoles Ca bound per mg protein. The effect of the lactose ingestion can be likened to the effect expected from continued high calcium intake, i.e., a decrease in the efficiency of calcium absorption and a decrease in CaBP.


A chick assay for determination of available iron from biological material and its application to fish protein concentrates.

A dose response assay for the assessment of available iron in biological materials using chicks as experimental animals is described. Day-old chicks were fed on an iron-deficient diet for 2 to 3 weeks at which time the hematocrit had decreased to about 20%. After this depletion period, the standard groups were fed graded levels of iron sulphate up to a maximum level of 30 ppm iron. The test groups were fed two levels of biological material giving a total dietary iron concentration within the standard range. The response was measured by hemoglobin concentration (g/100 ml), and the dose by the consumption of iron per gram of body weight gain. Contents of available iron (relative to iron sulphate-iron) in the test substances were calculated from the dose response regression equations obtained on the standard groups, and hemoglobin (g/100 ml), feed consumption and body weight gain in the test groups. Statistical evaluation of the data revealed that the assay complied with the requirement for statistical and fundamental validity. Results from application of the method on six different samples of fish protein concentrate (FPC) are reported.


Pyridoxine requirements of channel catfish.

In 20 and 12 week feeding trials, channel catfish fingerlings were fed purified diets containing five levels (0, 5, 10, 20, and 30 mg/kg) and six levels (0, 1, 2, 5, 10, and 20 mg/kg) of supplemental pyridoxine hydrochloride. Fish fed unsupplemented diets (pyridoxine content of 1.2 mg/kg) were characterized by anoxeria, nervous disorders, tetany, greenish-blue body coloration, and eventual mortality. Anemia, which has been reported in pyridoxine deficient salmonids, was not observed in pyridoxine deficient catfish. However, a microcytic, normochromic anemia was observed in groups fed high dietary levels of pyridoxine (20 mg/kg or greater). The dietary pyridoxine level required for maximal growth was approximately 3 mg/kg of diet. All other deficiency signs were prevented by 2.2 mg/kg of diet.


Increase in metabolic rate of the alligator fed proteins or amino acids.

Energy required for protein digestion, amino acid absorption and transport, and for protein synthesis in the alligator was estimated by determining oxygen consumption following feeding of single amino acids, various amino acid mixtures, fish, casein, gelatin, zein, and a gelatin hydrolysate. Results suggested a low energy requirement for protein digestion, for absorption of the released amino acids, and for amino acid transport, and a high energy requirement for protein synthesis. Little energy was needed for absorption and transport of neutral single amino acids but absorption of single ionic amino acids appeared to require energy. The alligator's metabolic rate is so low that processes requiring extra energy increased oxygen consumption as much as 300%. Peptide bond synthesis seems to have been responsible for the 3-fold increase in metabolic rate after feeding protein. Whether that phenomenon should be called "specific dynamic action" is problematical.


Effect of dietary Fe to Cu ratios on hematological and growth responses of broiler chickens.

A total of 2,640 broiler strain cockerels were used in three experiments to determine the interrelationships between Fe and Cu requirements of 1- to 21-day old broiler chicks. In each experiment, a starch non-fat milk basal diet was fed to chicks maintained in battery brooders beginning at 1 day of age. Maximum hemoglobin levels and packed cell volumes (PCV) of 21-day old chicks were found by feeding 80 parts per million (ppm) of dietary Fe and 8 ppm of dietary Cu from 1 to 21 days of age. The heaviest 21-day old chicks were found by feeding 80 ppm dietary Fe. Variations were found among experiments in the copper requirement based on body weight. The Cu requirement ranged from 8 to 16 ppm as indicated by 21-day old chick weights. A 10:1 dietary Fe to Cu ratio with an Fe requirement of 80 ppm appeared to maximize hemoglobin levels and PCV's of 21-day old broiler chicks; whereas, a 5:1 dietary Fe to Cu ratio, rather than a 10:1, 15:1, or 20:1 ratio, maximized 21-day old chick weights. Iron requirements for hematological and growth responses are essentially the same; however, the copper requirement may be slightly different for the two criteria.