Relationship of the pool of intracellular valine to protein synthesis and degradation in cultured cells.

To explore the role of the pool of intracellular free valine in the processes of protein synthesis and protein degradation, cultured hepatoma (HTC) cells were incubated in media containing varying concentrations of L-valine, under conditions of constant rates of protein synthesis and protein breakdown, and at steady state levels of intracellular valine specific radioactivities. Two types of experiments were compared: in the first (designated "incorporation experiment"), unlabeled cells were exposed to [3H]valine for a short period of time. In the second (termed "reincorporation experiment"), cells were prelabled with [3H]valine and then incubated for a brief period with media containing different concentrations of unlabeled valine; reincorporation of [3H]valine was calculated by the difference between the release of [3H]valine from labeled cellular proteins at low valine concentrations, and the maximal rate of the release at high valine concentrations. In both types of experiments, the rates of [3H]valine incorporation or reincorporation were compared with the respective specific radioactivities of free intracellular valine. In the incorporation experiment, the rates of [3H]valine incorporation into protein calculated by the intracellular specific radioactivities were not constant, but showed an upward deviation at low valine concentrations. This is in agreement with the results of Mortimore, G.E., Woodside, K.H., and Henry, J.E. ((1972) J. Biol. Chem. 247, 2776-2784) in the perfused rat liver. By contrast, in the reincorporation experiment, the calculated rates of [3H]valine reincorporation based on intracellular specific radioactivities were constant throughout the range of valine concentrations. The constant value of calculated valine reincorporation was lower by 30 to 50% than the calculated rate of valine incorporation at high valine concentrations. The following model is proposed to explain these results. There is one common pool of free intracellular valine, but there are two sites where valyl-tRNA can be formed. The first is an internal site that utilizes valine from the intracellular pool, and the second is an external (possibly membranous) system that converts extracellular valine directly to valyl-tRNA. Valine originating from protein degradation flows into the intracellular pool, from which it can be reutilized by the internal system. According to these assumptions, in the incorporation experiment and at low valine concentrations, the specific activity of valyl-tRNA is higher than that of the intracellular pool of free valine, due to the contribution of the external system. On the other hand, in the reincorporation experiment the specific activity of extracellular valine is negligible in comparison with that of the intracellular pool. Therefore, in this case the specific activity of valyl-tRNA is proportional to that of the intracellular pool, with a constant dilution by unlabeled valine of extracellular origin...


Collateral ligament laxity of the knee. Long-term comparison between plateau fractures and normal.

Bilateral varus-valgus knee-stress roentgenograms were made in 208 patients with unilateral single tibial-plateau fracture. Martin's so-called clear space was used to measure the laxity of the collateral ligaments and statistical analysis showed no increased laxity in the possibility injured ligaments. A vacuum phenomenon was produced in 36 per cent and ligament calcification was noted in 16 per cent of the knees tested.


Treatment of intertrochanteric and subtrochanteric fractures of the hip by the Ender method.

Ender's method of intramedullary fixation of intertrochanteric and subtrochanteric fractures is described. Ender's nail is a pre-bent flexible steel nail with a diameter of 4.5 millimeters. Three to five of these nails are inserted from a small incision proximal to the medial epicondyle of the femur into the medullary canal. They are passed through the femur across the fracture site and into the head of the femur, where they diverage. They are in the lines of force and therefore are not subjected to bending moments. The fracture fixation allows immediate weight-bearing. This method of fixation was used in a series of 203 patients. Their average age was sixty-eight years; the mortality rate was 10.3 per cent. In 3.9 per cent superficial infections occurred, but in no case was there a deep infection involving the bone. Functional return (walking) was achieved in all of the survivors who were able to walk at the time of injury, and there were no nonunions.


Extensive localized bone resorption in the femur following total hip replacement.

Extensive localized bone resorption within the femur was observed after four total hip replacements. The amount and location of the resorption suggested the presence of infection or tumor, but there was no evidence of either condition and the roentgenographic appearance differed from that associated with a loose uncemented endoprosthesis or a grossly loose femoral component of a total hip replacement. At reoperation the femoral components were not rigidly fixed but were only slightly loose. Histologically there were sheets of macrophages, a few giant cells, and multiple small fragments of a birefringent material, but no inflammatory cells. While the exact mechanism of this serious complication is unclear, the findings suggest that a benign, non-inflammatory, adverse tissue response can occur in relation to the femoral components of total hip replacements that are not rigidly fixed. In all four hips, reimplantation of a new total hip replacement was successful after follow-up of thirteen to eighteen months.


A stress analysis of the femoral stem in total hip prostheses.

A two-dimensional stress analysis was used to study the effects of some of the factors leading to early fatigue failure of the femoral stem in total hip prostheses. The results show that loss of proximal stem support at the level of the calcar femorale will result in stem stress levels which can lead to fatigue failure. In addition, the role of body weight and range of cyclic stress fluctuation play an important role in fatigue life under conditions where the stem has lost proximal support. These results indicate that stem design could be improved by incorporating some means of ensuring adequate support at the calcar femoralre maximum tensile stresses are found to occur.


Mechanical properties of the human thoracic spine as shown by three-dimensional load-displacement curves.

The mechanical properties of the human spine are best described by load-displacement curves which include coupling effects. Three-dimensional load-displacement curves were obtained for all levels of the human thoracic spine using fresh cadaver spines in an atmosphere containing 100 per cent humidity at 22 degrees centigrade to stimulate a physiological environment. Six forces and six moments were applied, one at a time, to the center of the upper vertebra while its subadjacent fellow was fixed. Assuming sagittal plane symmetry, vertebral displacement was measured in three-dimensional space and load-displacement curves were plotted for the main as well as the coupled motions. The thirty-six curves necessary to define the mechanical characteristics of each motion segment completely were determined for all eleven thoracic levels. The curves showed that all the thoracic spine is a complex three-dimensional structure with coupled motion characteristics. Axial forces (compression/tension) resulted in significant horizontal displacements. Spine motion segments were more flexible in flexion than in extension. The spine was found to be least flexible during axial compression.


Fractures in thalassemia.

Fractures occur frequently in patients with homozygous beta-thalassemia. A study was made of the fractures noted in a group of patients who were followed at the Thalassemia Clinic at The New York Hospital-Cornell Medical Center. Results indicate that these patients often sustain fractures which are multiple and which frequently heal with resultant deformities.


Capsulodesis of the metacarpophalangeal joint of the thumb in children with cerebral palsy.

A deformity of hyperextension of the metacarpophalangeal joint of the thumb occurring in thirteen children with spastic cerebral palsy was corrected by capsulodesis of the joint. The technique involves shifting the metacarpal attachment of the volar plate more proximally in the metacarpal. When combined with selective release of the involved intrinsic muscles and selective transfer of the extrinsic motors, when indicated, the thumb is brough away from the palm and its function and appearance are improved. Moreover, there is not risk to growth of the thumb such as might follow arthrodesis in a growing child. Results were satisfactory except in two athetoid patients, in whom some of the intial correction was lost, but even their thumbs did not revert into hyperextension. In five patients, for reasons not entirely clear, the previously flexed interphalangeal joint had better extension postoperatively. This improved the function of the thumb, because the broad pulp of the thumb could then be used firmly against the side of the index finger.


Acute rupture of the peroneal retinaculum.

The anatomy of the superior peroneal retinaculum at the ankle includes a sheath somewhat distinct from a fibrous lip extending from the periosteum of the fibula at the lateral aspect of the lip of the groove. In seventy-three cases of injury to the retinaculum, three grades of injury were recognized. Surgical repair was quite successful except in three cases.


Chondrosarcoma: clear-cell variant. A report of sixteen cases.

Of sixteen adult patients with clear-cell chondrosarcoma, ten were men. The tumor usually involved the proximal part of the femur or humerus. Roentgenographically, the lesion was usually well defined and indistinguishable from chondroblastoma. Serial roentgenograms occasionally showed malignant progression of the lesion. Histologically, benign giant cells and cells with clear cytoplasm were always present, and areas of conventional chondrosarcoma were seen in about half the cases. Excision usually resulted in recurrence; resection seemed to be curative. Four of the sixteen patients died as a result of the tumor. Clear-cell chondrosarcoma should be distinguished from chondroblastoma and treated more aggressively.


Femoral-neck fractures in young adults.

Twenty-two young adult patients with femoral-neck fractures fitting the following criteria were evaluated. All patients (1) were between twenty and forty years old, (2) had clinical and follow-up roentgenograms at least twelve months after the injury, (3) incurred fracture of the neck of the femur through normal bone, and (4) did not incur a stress fracture. The incidence of non-union was 59 per cent (thirteen of twenty-two patients) and of avascular necrosis, 86 per cent (nineteen of twenty-two patients). Evaluation of patients and results are discussed.


Hip dysplasia in the African Bantu.

Dysplasia of the hip is almost unknown in the Bantu peoples of Africa, except in cases of arthrogryposis and in those with partly European ancestry. Evidence is produced to show that the importance of intrinsic genetic factors in hip dysplasia far outweighs that of the extrinsic factors. These are of great importance only if allowed to act on a hip in which genetic factors have already determined dysplasia. Evidence is also produced to contradict the theory that the "piggyback" carrying method used by Bantu mothers is the reason for the immunity from dysplasia of the hip. The absence of "primary" osteoarthritis of the hip is noted, and the range of hip disorders leading to "secondary" osteoarthritis in the adult African is compared with that in the adult European. Three patients are described, one in each of the groups mentioned above, the third having an isolated "typical" congenital dislocation of one hip. The methods of study used were enquiry into obstetric history and into carrying methods, and arthrography to confirm clinical findings. The experience of other surgeons working in Africa is recorded.


The shelf operation for hip dysplasia in adolescence.

Failure of normal acetabular development is inevitable in congenital dislocation of the hip when it is unrecognised until late infancy or early childhood. Numerous stabilising procedures have been described, one of the first being the shelf operation or acetabuloplasty. This procedure fell into disrepute because the shelf was often located too high or was too small to prevent upward migration of the femoral head. The technique described emphasises the importance of resecting the thickened capsule and exposing the lateral margin of the acetabulum to allow a substantial portion of the outer cortex of the ilium to be turned down both laterally and anteriorly over the femoral head. Twenty cases of acetabuloplasty have been followed up for an average period of nine years. The results have been assessed from the point of view of function, relief of pain, and degree of support of the femoral head as demonstrated radiologically. The shelf operation is a simple and safe procedure, and provided it gives adequate support to the subluxated femoral head it will ensure a stable, mobile joint capable of standing up to reasonable use for many years. If deterioration should occur in later life, total hip replacement may be undertaken more easily than if the joint had been allowed to undergo progressive subluxation.


The pelvic osteotomy of Chiari: an anatomical study of the hazards and misleading radiographic appearances.

The medial displacement osteotomy of Chiari has an established place in the management of older children and adults with severe hip dysplasia. The results claimed for the operation are, however, variable. There have also been reports of sciatic nerve lesions. In this study ten cadavers were operated upon. Chiari osteotomy was performed upon five, and five acted as controls. The hemipelvis was removed from each cadaver; each specimen was deep-frozen and sectioned transversely. The distance of the sciatic nerve from the nearest bony point was measured in each section and the results were recorded graphically. A further radiographic and photographic study was performed to determine whether apparent displacement at the osteotomy might be misleading. The conclusion was drawn that the sciatic nerve is angulated at the osteotomy and further endangered by the risk of bone splintering at the sciatic notch. The radiographic study suggested that some poor clinical results may be explained by a radiological artefact, because there is a tendency for the osteotomy to hinge posteriorly at the sciatic notch opening anteriorly like a book. Radiographs may suggest excellent medial displacement whereas in fact the femoral head is very poorly covered.


Slipping of the upper femoral epiphyses in patients with intracranial tumours causing hypopituitarism and chiasmal compression.

Four cases of slipped upper femoral epiphyses in patients with intracranial tumours causing hypopituitarism and chiasmal compression are presented. Detailed endocrine studies in three cases showed severe deficiencies of growth hormone as well as of gonadotrophin and sex hormones. The literature is reviewed and the aetiology is discussed with special reference to Harris's hypothesis that an increase in growth hormone relative to oestrogen predisposes to slipping of the upper femoral epiphysis in humans, which these cases do not seem to support. In all cases the slip was bilateral, and it is emphasised that surgical treatment can provide only temporary fixation because fusion is dependent on correct hormonal therapy.


Patterns of osteoarthritis of the hip.

The division of osteoarthritis into primary and secondary varieties implies that these are aetiologically distinct entities, the former being due to some intrinsic defect of cartilage and the latter resulting from previous articular damage. This traditional concept is questioned and the hypothesis is advanced that osteoarthritis is always secondary to some underlying abnormality of the joint. A detailed clinical, radiographic and morbid anatomical study of 327 cases of osteoarthritis of the hip is presented. In all but twenty-seven some predisposing abnormality of the joint was diagnosed: 107 (33%) were associated with major pathology such as Perthes' disease or epiphysiolysis; minor acetabular dysplasia was present in sixty-seven (20%), with a male: female ratio of 1:10; minimal femoral head tilt was demonstrated in fifty-nine (18%), the male: female ratio being 14:1; and in forty-three (13%) there were features suggesting an underlying inflammatory arthritis. On the basis of this study a new classification is proposed and osteoarthritis of the hip is divided into three pathogenetic groups: 1) failure of essentially normal cartilage subjected to abnormal or incongruous loading for long periods; 2) damaged or defective cartilage failing under normal conditions of loading; 3) break-up of articular cartilage due to defective subchondral bone.


Degenerative spondylolisthesis.

A clinical study has been made of forty-three patients with symptoms arising from degenerative spondylolisthesis of the lumbar spine. Attention is drawn to the lower average level of the iliac crests in these patients, and to the high incidence of osteoarthritis of the hips. Many patients in this series had been referred specifically for operation and fourteen were so treated. The techniques of decompression and of spinal fusion are discussed. It is concluded that patients with back pain predominant are well treated by corsetry, only a minority needing fusion, and that patients with nerve root involvement or with symptoms of spinal stenosis need decompression. The place of spinal fusion is the main problem, but it seems reasonable, firstly, in younger patients with clear evidence of instability and degenerative change at a single level, and secondly, when radical decompression is judged to increase the risk of instability.


Observations on the management of failed spinal operations.

A system is presented for the analysis of failure after spinal operations: 1) outright failure; 2) temporary relief; 3) failure in spondylolisthesis; and 4) infections. With this system it is possible to trace the causes of failure and to correct some of them. When they are used as a guide before operation, the recommendations made should help to prevent many failures.


Muscle imbalance in the aetiology of scoliosis.

At the apex of an idiopathic scoliotic curve there is a greater proportion of "slow twitch" muscle fibres in multifidus on the convex as compared to the concave side. To determine whether this represents a primary muscular imbalance relevant to the aetiology of idiopathic scoliosis or merely a secondary change, the lengths of multifidus on opposite sides of the curve were measured. Multifidus is shorter on the convex side. This is consistent with the theory of primary muscular imbalance, in which the more tonically acting muscle with its higher proportion of "slow twitch" fibres contracts and shortens as the deformity is produced. The paradox of multifidus being shorter on the convex rather than on the concave side is explained by consideration of its action.


Malignant osteoblastoma.

The clinical, radiographic and pathological features are described of eight cases of a bone tumour which we propose to classify as "malignant osteoblastoma". It presents the characteristics of genuine osteoblastoma but of an aggressive pattern, with more abundant and often plump hyperchromatic nuclei, greater nuclear atypia, and numerous giant cells of osteoclastic type. This rare tumour is regarded as the malignant counterpart of osteoblastoma and appears to be only locally aggressive. It should be separated from conventional osteosarcoma not only because of its peculiar histological pattern, but also because of its different clinical and radiological features and better prognosis. Thus seven of the eight patients were alive and free of disease from one and a half to eleven years after the initial surgical treatment, which in only two cases included amputation. Excision or block resection is the preferred method of treatment.


Transposition of the tendon of pronator teres in cerebral palsy.

We have considered the indications for and results of transplanting pronator teres to extensor carpi radialis brevis in cerebral palsy. The operation has some virtue but a very limited application. We achieved satisfactory functional results in six of nine patients and some improvement in one. Two operations failed because of poor selection. In all patients the appearance of the limb was improved.


Tenodesis of flexor hallucis longus for paralytic clawing of the hallux in childhood.

Paralytic clawing of the hallux may occur in children with congenital disorders of the neuraxis. Tenodesis of flexor hallucis longus allows correction of this deformity in early childhood. Seventeen of these procedures have been reviewed and good results were obtained in fifteen.


Excision arthroplasty of the elbow in rheumatoid disease.

The results of ten excision arthroplasties of the elbow for rheumatoid disease are described. The operation may afford good relief of pain and a useful increase both of hinge motion and of forearm rotation. Instability is not a serious problem unless the patient has to bear weight on crutches. To increase stability after arthroplasty it appears that Kirschner wire fixation is advisable as well as a plaster cast. For advanced rheumatoid disease unilateral excision arthroplasty has a definite value, especially for patients confined to a wheelchair.


Acute dislocation of the patella with osteochondral fracture: a review of eighteen cases.

Eighteen patients with acute dislocation of the patella had associated osteochondral fractures. This fracture complicates approximately 5% of all acute dislocations of the patella occurring in children. Three types of fracture patterns were noted. All patients who were treated by immediate arthrotomy and excision or replacement of the osteochondral fragment and repair of the acute dislocation of the patella made an uneventful recovery with no recurrence of the dislocation. In those patients in whom the osteochondral fragment was removed but with no repair the dislocation recurred.


Compression of the common peroneal nerve by intramuscular ganglion from the superior tibio-fibular joint.

Eight patients had symptoms from ganglia arising from the superior tibio-fibular joint with physical signs that resembled the anterior tibial and peroneal compartment syndromes. Five ganglia were in the peroneus longus muscle in which they produced only an ill-defined firmness. Histologically the ganglia showed much cellular activity which must not be mistaken for malignant change.


Local osteo-articular tuberculosis complicating closed fractures: report of two cases.

The localisation of acute haematogenous pyogenic osteomyelitis following a local injury is well known. Whilst there is often a history of trauma in patients developing bone and joint tuberculosis, its role is obscure. Two patients are reported who developed histologically proven tuberculosis in the vicinity of closed fractures during the healing process. These two patients make a total of four so far reported.


[Metaphyseal channel and serpiginous tract in osteomyelitis: literature review apropos of 2 cases].

The so-called "metaphyseal channel" and "serpiginous tract" signs are described in detail, emphasizing their value in the roentgen diagnosis and differential diagnosis of some bone lesions. The authors present two cases of osteomyelitis, one of the chronic type and the other subacute in two adult patients, to illustrate the value of the above radiologic signs. These have been previously described in the long bones of infants and children only. The serpiginous tract sign is reported, for the first time, in a flat bone.


Osteomyelitis and septic arthritis complicating hand injuries and infections: pathogenesis of roentgenographic abnormalities.

Osteomyelitis and pyarthrosis may complicate hand injuries and soft-tissue infections, resulting in characteristic radiographic findings. Evaluation of 78 patients revealed bone or joint abnormalities in 10% of individuals. Distinct pathways are available for spread of bacteria which become lodged in the soft tissues of the hand. Such routes include tendon sheaths, fascial planes and lymphatics. An understanding or pertinent anatomy allows the radiologist to predict the site and pattern of soft tissue, articular and osseous alterations.


Inter-relationship between radiocarpal and metacarpophalangeal joint deformities in rheumatoid arthritis.

The roentgen evaluation of 96 rheumatoid hands and wrists, supplemented with anatomic and pathologic material from cadavers and patients with rheumatoid arthritis, allowed evaluation of deformities at the radiocarpal and metacarpophalangeal articulations. Measurements of specific coordinates in these patients were compared to those in "controls" and, despite significant error introduced by variability in patient positioning during radiography, definite inter-relationships between radiocarpal and metacarpophalangeal malalignments became evident. Radial deviation at the wrist was associated with ulnar deviation of the digits producing the "zig-zig" deformity of the rheumatoid hand. The pathogenetic and therapeutic aspects of the roentgen findings are discussed.


Direct magnification radiography of the chest in diffuse pulmonary disease.

The technique of direct magnification radiography of the lung in diffuse lung disease is very simple to perform. It is probably of value in selected cases where there is clinical suspicion of diffuse lung disease and when the plain radiograph is either normal or inconclusive. It is speculated that the air bronchiologram pattern seen on these radiographs is due to peribronchiolar parenchymal lung disease involving the parenchymal or acinar interstitial space with focal intra-alveolar involvement. An attempt to correlate these morphologic patterns with various pulmonary diseases is also stressed.


The value of preoperative saphenous venography for graft evaluation in femoral arterial occlusive disease.

We reviewed the results of preoperative bilateral ascending phlebography in 23 patients who had femoral arterial occlusive disease; seven of the 40 successful saphenous venograms showed significant abnormalities. Varicosities, congenital duplications, superficial or deep thrombophlebitis and saphenous vein length were clearly identifiable. Correlation of the radiographic sphenous diameter with the operative measurement was poor. Nevertheless, four of the 21 patients were spared unnecessary surgery because we had determined by preoperative venography a better vein for autograft than the ipsilateral saphenous vein.


Xanthogranulomatous pyelonephritis.

Xanthogranulomatous pyelonephritis is a stage in the progress of chronic pyelonephritis characterized by a combination of clinical and radiologic findings which suggest the diagnosis. Pathologically there are xanthogranulomatous deposits and large lipid-filled foam cells. These clinical-radiologic-pathologic features are demonstrated by means of a case report.


The application of xeroradiography in diagnosis of maxillofacial problems.

The evaluation of maxillofacial pathology was undertaken using xeroradiography. The edge enhancement and wide image latitude were shown to give additional information, especially in areas of bony overlap, such as the temporomandibular joint, without resorting to tomography. Other areas of possible utilization are also discussed, including sialography.


Sialography in metastases to lymph nodes of the parotid gland.

The subject of metastases to the lymph nodes of the parotid gland is reviewed and the sialographic features in two cases are described. The sialographic appearance in these cases is indistinguishable from that found in primary parotid neoplasms.


The right pleuromediastinal reflection in children.

The authors review the anatomy of the pleural reflection of the right lung against the middle mediastinum in childhood. In 505 consecutive normal frontal radiographs of children, from birth to sixteen years, this pleural reflection (also known as the pleuro-esophageal line) was visible in 83%. The entire reflection from thoracic inlet to diaphragm was clearly seen in 13%, chiefly in upright, deep-inspiration, well penetrated radiographs. It is a radiographic landmark in the middle mediastinum, particularly well seen in childhood, and its use in assessment of mass lesions, cardiomegaly and lung collapse is described.


Incorporation of (3H)uridine by the chromatoid body during rat spermatogenesis.

The in vitro incorporation of tritiated uridine into RNA by the spermatogenic cells of the rat has been analyzed by high-resolution autoradiography. Special attention has been focused on the unique cytoplasmic organelle, the chromatoid body. After a short labeling time (2 h), this organelle remains unlabeled in the vast majority of the early spermatids although the nuclei are labeled. When the 2-h incubation with (3H)uridine is followed by a 14-h chase, the chromatoid body is seen distinctly labeled in all spermatids during early spermiogenesis from step 1 to step 8. Very few grains are seen elsewhere in the cytoplasm of these cells. When RNA synthesis in the spermatid ceases, the chromatoid body also remains unlabeled. It is likely that the chromatoid body contains RNA which is synthesized in the nuclei of the spermatids. The function of this RNA as a stable messenger RNA needed for the regulation of late spermiogenesis is discussed.


Equilibrium and kinetic effects of drugs on the shapes of human erythrocytes.

We have previously proposed that if the two half-layers of a membrane are different in their protein and lipid compositions, they may respond differently to some membrane perturbation (the bilayer couple hypothesis). This hypothesis has been applied to explain the changes in shape of human erythrocytes that are produced by a variety of amphipathic compounds. These compounds are presumed to intercalate by their hydrophobic ends into the lipid portions of the membrane; if the compounds are anions, the binding is preferentially to the outer half of the bilayer, if cations, to the inner half. It is proposed that such preferential binding causes an expansion of one half-layer relative to the other, with a corresponding change in cell shape. The predicted sidedness of these shape changes is now demonstrated in experiments with methochlorpromazine and 2,4,6-trinitrophenol. Under appropriate nonequilibrium or equilibrium or equilibrium conditions, both of these compounds are shown to be either crenators or cup-formers of the intact erythrocyte, depending upon which side of the membrane they are concentrated in. These results therefore strongly support the bilayer couple hypothesis.


RNA synthesis in preovulatory mouse oocytes.

RNA synthesis, previously shown to take place during oocyte growth, has been demonstrated throughout the growth-quiescent period preceding ovulation of the mouse oocyte. In the final 7-day preovulatory period, the level of incorporation of (5,6-3H)uridine into ovulated oocytes decreased as the interval between exposure to precursor and ovulation decreased; significant incorporation was detectable within 2 days before ovulation. Analysis of the frequency and density of label in ovarian oocytes at successive stages of meiosis in relation to the interval between adminstration of labeled precursor and collection of oocytes revealed that RNA synthesis continues up to within 2 h before GVBD.


Dynamic changes of the luminal plasmalemma in stimulated parotid acinar cells. A freeze-fracture study.

In the acinar cells of the rat parotid gland the two membranes participating in exocytosis, i.e., the luminal plasmalemma and the secretory granule membrane, are clearly distinguishable in freeze-fracture because of their different densities in particles. In order to obtain point-specific information about the fusion-fission of these two membranes that occurs during the secretory cycle, glands were studied at various times (5 min to 6 h) after stimulation with isoproterenol. We observed that, in the course of the release of secretion products and shortly afterwards, the enlarged luminal plasmalemma exhibits a mosaic organization consisting of an alternation of membrane patches of high (original plasmalemma) and low (fused granule membrane) particle density. The transition between these two patterns is usually sharp. Later, concomitant with the reformation of acinar canaliculi, the low particle density membrane is found at the cell surface but only bounding vacuolar infoldings, and then it finally disappears. These results suggest that (a) fusion of these membranes does not result in a random intermixing of the molecular components of the participating membranes, which retain their structural identity; and (b) the enlarged luminal plasmalemma reverts to its original size by a progressive, specific removal of the regions of low particle density from the cell surface.


Peroxidase uptake by photoreceptor terminals of the skate retina.

The photoreceptors of dark-adapted skate retinas bathed in a Ringer solution containing horseradish peroxidase (HRP) incorporate the tracer into membrane-bound compartments within the synaptic terminal of the cell; after 1 or 2 h of incubation, approx. 10-38% of the synaptic vesicles were labeled. The receptors appeared to be functioning normally throughout the incubation period, since electrical potentials of normal amplitude could be elicited in response to dimphotic stimuli. However, it was possible to block the uptake of peroxidase by a regimen of light adaptation that effectively suppressed light-induced activity in the electroretinogram. If, during incubation with peroxidase, retinas were exposed at 10-min intervals to an intense 1-ms flash from a xenon discharge tube, the receptor terminals were almost completely devoid of peroxidase; fewer than 2% of the vesicles were labeled. The suppression of HRP uptake could also be achieved in dark-adapted retinas by adding magnesium to the bathing solution, suggesting that calcium is necessary for transmitter release from vesicles in the receptor terminals. These findings are consistent with the view that vertebrate photoreceptors discharge a neurotransmitter in darkness, and that light decreases the release of this substance. It seems likely that the incorporation of peroxidase into vesicles of physiologically active receptor terminals reflects a mechanism for the retrieval of vesicle membrane after exocytosis.


Dependence of centriole formation on protein synthesis.

Centriole formation was studied after inhibition of protein synthesis for various portions of the cell cycle. Synchronous populations of mitotic L929 (mouse) cells were plated into petri dishes and the course of procentriole formation was monitored by electron microscope analysis. The frequency with which procentrioles were seen in association with mature centrioles normally increased steadily in the interval from 4 to 12 h after mitosis. The formation of procentrioles was abruptly inhibited by the addition of cycloheximide at any time from mitosis until 12 h postmitosis (S phase). This suggested that the formation of procentrioles was dependent upon protein synthesis immediately before their appearance. Prophase-accociated elongation of procentrioles appeared to occur normally in cells treated with cycloheximide for up to 4 h before prophase, though the mitotic index in treated cultures decreased somewhat. Thus, protein synthesis did not appear to be essential for procentriolar elongation to the mature length.


Elimination by Hydra interstitial and nerve cells by means of colchicine.

Hydra treated with colchicine or Colcemid become depleted of 95-99% of their interstitial cells and derivatives of this stem cell: nematoblasts, nematocytes and nerve cells. A second treatment removes most or all remaining interstitial cells. The most effective treatment is an 8-h immersion of whole Hydra attenuata in 0.04% Colcemid or 0.4% colchicine. Interstitial cells are eliminated through phagocytosis by both ectodermal and endodermal epithelial cells. The endodermal digestive cells send processes through the mesoglea which engulf interstitial cells and retract them into the endoderm. The resultant hydra, though devoid of nematocysts, can be artificially fed: these animals grow and bud and can be used to study the behaviour and development of tissue lacking nerve and interstitial cells.


Cell-to-substrate contacts in living fibroblasts: an interference reflexion study with an evaluation of the technique.

The closeness of contact between cultured chick heart fibroblasts and glass substrates has been examined by interference reflexion microscopy. Evaluation of the optical technique demonstrated that both the film of medium between the cell and substrate and the cell itself act as two superimposed thin films which generate a complex interference pattern in reflected light or low illuminating numerical aperture (I.N.A.). The interference pattern generated by the cell consists of first and higher orders of interference and can be eliminated from the image by increasing the I.N.A. to greater than 1.0. The residual zero-order interference pattern at high I.N.A. originates from the thin film of medium between cell and substrate and corresponds to the closeness of contact between cell and substrate. Based on the zero-order interference pattern and a comparison of the same cells with differential interference optics, the following features were recognized in living chick heart fibroblasts. Focal contacts, 0.25-0.5 mum wide, 2-10 mum long, separated by 10-15 nm from the substrate, are located under the peripheral regions of the leading lamellae and near the edge of extended non-spreading regions of the cell margin in moving and stationary cells. Individual focal contacts are coincident with cytoplasmic fibres of the same dimensions as the contact or with the peripheral ends of longer fibres that extend from the focal contact toward the centre of the cell. In spreading cells a second type of contact is present under the peripheral regions of the leading lamellae. This close contact consists of a broad area of uniform cell-to-substrate separation distance (ca. 30 nm). Focal contacts are distributed within the close contact under the leading lamellae. Lamellipodia extend ahead of the close contact and are separated by 100 nm or more from the substrate. Depending on the previous motile history of the cell, the close contact extends to varying degrees under the centre of the cell but it is typically dissected here by discrete areas of distinctly greater cell-to-substrate separation (100-140 nm). Evidence for the adhesive nature of the focal contacts is considered. The common identity is discussed of the focal contacts and associated cytoplasmic fibres described here in living cells with the regions of closest apposition to the substrate and associated cytoplasmic plaques and bundles of microfilaments seen in EM studies.


Distribution and dynamics of nematocyte populations in Hydra attenuata.

The distribution and dynamics of the 4 nematocyte populations of Hydra attenuata were investigated. Ninety-seven per cent of all nematocytes, including all 4 types, are mounted in the battery cells of the tentacles. The remaining 3%, including 2 types (stenoteles and holotrichous isorhizas) are mounted in the ectoderm of the body column. Eight-two per cent of all nematocytes are desmonemes; 11%, atrichous isorhizas; 5%, stenoteles; and 2%, holotrichous isorhizas. The density of each nematocyte population increases along the length of the tentacle towards the tip. The percentages of the total nematocytes per quarter of tentacle for each of the 4 quarters starting at the base is 15, 18, 25 and 42% respectively. The turnover time of the nematocyte populations in the tentacles was measured with 2 methods. First, the transit time for a carbon-marked battery cell from the base to the tip of the tentacle was measured. Secondly, the time required to replace the unlabelled nematocytes in the tentacles with [3H]proline-labelled nematocytes was measured. In both cases the time was 7--9 days. Based on these data (distribution and turnover time) a model was constructed for the dynamics of the nematocyte populations in the tentacles. The numbers of nematocytes produced dialy in the body column as predicted by the model are in reasonable agreement with the measured values.


An ultrastructural and radioautographic study of the chromocentric interphase nucleus in plant meristematic cells (Raphanus sativus).

In Raphanus sativus, the mitotic chromosomes are quite short and, on reaching the cell poles, soon undergo extensive unravelling. By late telophase and early interphase, only a few chromosome segments, believed to correspond to the centromeric regions, are still visible in the form of chromocentres closely associated with the nuclear envelope. Although interphase nuclei show little internal structural differentiation, high-resolution radioautography has permitted us to establish which of them have reached the early, mid and late S periods. In early S nuclei, only the nucleolus and the euchromatin which pervades the nuclear cavity become labelled. By the mid S-period, the diffuse chromatin and nucleolus incorporate less thymidine and DNA synthesis is initiated within the peripheral chromocentres. Subsequently, the radioautographic grains become restricted to the chromocentres. The finding that certain late S nuclei exhibit loosely organized chromocentres strongly suggests that these heterochromatic chromosome segments undergo important conformational modifications during DNA replication. Finally, the presence of radioautographic grains over the lacunar regions of the nucleolus in early and mid S nuclei demonstrates that intranucleolar DNA replicates during the earlier portion of the S-period.


Relations between the nuclear activity and the variable 3H-amino acid incorporation pattern in Amoeba proteus.

Tracer kinetic studies have revealed the existence of a variable pattern of 3H-amino acid incorporation into amoeba proteins during the early G2 phase of the cell cycle. Two peaks of incorporation of [3H]leucine were found to occur at 19 and 22 h, whereas a single peak at 17 h was noticed in the amoebae labelled with [3H]lysine. An almost 2-fold increase of the labelled amino acid incorporation occurred during the peak periods, while the other periods showed a more or less steady state of incorporation, suggesting a basal rate of synthesis at these times. In a detailed study involving the peaks and the basal incorporation period of [3H]leucine, it was shown that the removal of the nucleus or Actinomycin D treatment eliminated the peaks but the base line protein synthesis was not affected. This suggests that for the peak synthetic periods, mRNA is probably transcribed concurrently, followed by immediate translation, whereas long-life mRNA accounts for the basal synthetic activity.


Cell size and proportional distance assessment during determination of organelle position in the cortex of the ciliate Tetrahymena.

Developing oral organelles of dividing Tetrahymena corlissi appear to be positioned by mechanisms which assess distances as a proportion of the organism's overall dimensions. In some respects, the cortex of this protozoan obeys the 'French flag' rule formulated by Wolpert for describing regulation of spatial proportions during differentiation of metazoan embryos. Dividing Tetrahymena of markedly different sizes occur when division is synchronized by starvation and refeeding. At the start of cell division, the distance between old and new mouthparts varies proportionately with respect to cell length. In addition, determination of the site where new oral organelles will develop is apparently not directly related to the number of ciliated basal bodies which separate the 2 sets of mouthparts; the greater the distance between the old and developing sets of mouthparts, the greater the number of ciliated basal bodies in the rows between them. It is suggested that 2 distinct mechanisms are largely responsible for defining organelle position in ciliates. The new terms structural positioning and chemical signalling are defined to describe these mechanisms.


The chitin crystallite in arthropod cuticle.

Electron microscopy has revealed that chitin from a representative selection of insect orders (plus one crustacean and one arachnid) is localized in crystallites about 2.8 nm across. Furthermore, these crystallites are arranged on an hexagonal or pseudo-hexagonal lattice, the lateral order of which varies considerably. The lattice becomes secondarily reoriented during cuticle expansion following an ecdysis. The size of the 'unit cell' has been measured both by optical diffraction and direct measurements of the micrographs, permitting an estimate of the chitin and resilin content for locust rubberlike cuticle. The number of poly-N-acetyl-glucosamine chains per sheet and sheets per crystallite can be estimated from the physical dimensions of the crystallite. Each crystallite is unlikely to comprise more than 3 sheets and 6 chains per sheet. The calculated and measured density of alpha-chitin can be shown to be in close agreement.


A three-dimensional reconstruction of the polygonal pattern on placental coated-vesicle membranes.

There is a surface structure on the coated vesicles of human placenta. Some features of this structure have been examined. Measurements of the polygonal network seen in surface views have been made and compared with measurements of structures projecting from vesicle walls in median sections. A 3-dimensional reconstruction of the vesicle shows the pattern to be one of raised ridges. Use of a goniometer to tilt the specimens has confirmed the assumption that both types of image obtained as from one structure. Although it is usually the case that vesicles are approximately spherical, some are definitely irregularly shaped. For this reason it is suggested that the walls of the polygons need not always be packed into a structure with a regular and precisely maintained pattern. Consideration of the surface structure in the light of current understanding of the cell membrane as a dynamic system leads to a possible explanation of the process of vesicle formation in this context and of the selective nature of uptake by micropinocytosis.


Organization of intramembrane particles in freeze-cleaved gap junctions of rat graafian rollicles: optical-diffraction analysis.

Gap junctions were identified in the membrana granulosa and cumulus oophorus, and between cells of the internal theca, of the preovulatory rat follicle. In replicas of freeze fractured follicles, the A face presented clusters of closely packed intramembrane particles, 7--9 nm in diameter, forming a mosaic pattern, while the B face showed a similar pattern of small pits. Optical diffraction analysis of these electron micrographs revealed that both the intramembrane particles and the corresponding pits were organized in hexagonal lattices with centre-to-centre spacing of 9-10 nm. In small junctions (up to 0.4 mum in diameter), both A and B faces generally consisted of a single lattice, while large junctions (0.5-2 mum) contained multiple lattices differing in orientation. Occasionally intramembrane particles and pits were more loosely arranged throughout the junctional area and failed to show a hexagonal pattern. Both granulosa and thecal cells often contained intracellular vesicles resembling annular junctions. These contained intramembrane particles whose assembly resembled that of the gap junctions with regard to periodicity and lattice organization. Examination of thin section of thin sections suggested that small gap junctions occur also between cytoplasmic processes of coronal cells and the oolemma. No tight junctions were detected between granulosa cells and between thecal cells.


[Ischemia or acute vascular stasis of a limb related to psychopathological behavior. Pathominia].

Disorders due to voluntary use of a tourniquet may produce numerous therapeutic errors with serious consequences. The difficult diagnosis of this hysterical behavior is recalled here and the authors report two cases.


[Surgical treatment of pulmonary metastases from rectocolic cancers. Apropos of 21 cases].

The authors report 21 cases of pulmonary metastases from operated cases of rectal and colonic carcinoma. Half the patients were aged between 60 and 70 years. In all cases except one the primary tumour was known and treated surgically before the metastasis occurred. The authors emphasize the necessity of radiological supervision of the chest after operation and recall that neither chemotherapy nor radiotherapy should be undertaken without prior histological confirmation. It is possible to remove the metastases by surgery but a high percentage require pneumonectomy i.e. it is necessary to take the same precautions before operation as for primary carcinoma of the bronchus. The operative mortality was nil, and the five year survival rate 18 p. 100.


[A rare complication of the acetabulum: incarceration of a small intestine loop in the fracture area].

The authors report an exceptional case of fracture of the acetabulum complicated by tear of the small intestine due to injury to the loop of intestine by a piece of the fractured acetabulum. As it is rare, such a complication is often undiagnosed. Discovered in time, an operation avoids a fatal issue due to peritonitis.


[Thoracic and abdominal lesions in multiple injuries. Study of 168 cases. Remarks on problems posed by assessment of the lesions].

A statistical study of 168 cases of multiple injury observed by the authors, showed the importance of lesions of the trunk with 65 p. 100 thoracic and 73 p. 100 abdominal injuries. All cases ofmultiple injury with thoracic or abdominal injuries require early, complete assessment. This emergency assessment is perfectible by using a planned approach to these cases and the application of certain methods of investigation. The authors propose three organigrams in order to define the best management for cases with thoracic, abdominal or urinary injuries.


[Bone echinococcosis. Apropos of a case of hydatid cyst of the spine].

The authors report a case of hydatid cyst of the vertebral column (L2-L3) simulating an acute abdominal syndrome with pain in the right iliac fossa. On exploration of the abdominal cavity, they detected the presence of a fluctuating retroperitoneal collection of fluid due to the migration of a hydatid abscess into the sheath of the right psoas muscle. Three surgical operations of curetage followed by wide drainage were carried out with simple operative sequelae.


[Pregnancy and breast cancer: 2 entities with complex interferences. Critical study of the dossier].

The author reviews the epidemiological, biological and clinical data concerning the association of carcinoma of the breast and pregnancy. He discusses, in particular, the therapeutic problems raised by this association. The author attracts attention to the fact that in certain circumstances, pregnancy may aggravate the disease, whilst in others, it seems to protect with regard to the cancer. As far as the therapeutic problems are concerned, he emphasizes in particular, the following conclusions: 1) in cases which require surgery, the prognosis is less poor than generally believed; 2) the total inefficacy of therapeutic abortion is now certain; 3) radiotherapy and chemotherapy should be prohibited during pregnancy; 4) a pregnancy occurring during the years following mastectomy for carcinoma, does not seem to have the unfavourable prognosis which was originally believed.


Derivatization of compounds at the origin of thin-layer plates with fluorescamine.

A method has been developed for the detection of compounds with primary amino groups on thin-layer chromatography (TLC) plates with fluorescamine. The compounds dissolved in buffer were applied to TLC plates and derivatized at the origin by developing with or dipping into an acetone-hexane solution of fluorescamine. Virtually all fluorescamine derivatives stayed at the origin, and they were subsequently separated using appropriate solvent systems. As little as 10 pmoles of fluorescamine-derivatized compound could be detected when viewed under a long-wave (366 nm) ultraviolet lamp. The method was applied to the analysis of peptides, amino acids and amines.


Determination of urinary monohydric and dihydric phenols by gas chromatography of the acetate and TMS derivatives. 4-Dimethylaminopyridine as a catalyst for acetylation reactions.

A procedure is described for the quantitative extraction of phenols from human urine. The compounds were chromatographed as the trimethylsilyl derivatives on wall-coated glass capillary columns. A more specific method of extraction involving the formation of acetate derivatives is also described. The acetates were prepared by treating dilute solutions of phenols at room temperature with acetic anhydride in the presence of 4-dimethylaminopyridine, which is a far more powerful catalyst than pyridine. Under these conditions N-acylamino acids are converted to azlactones.


Separation of chymopapain from papaya latex (Carica papaya) on amberlite IR-120 (Hg2+).

The quantitative separation of chymopapain from papaya latex has been carried out by chromatography on Amberlite IR-120 (Hg2+). The product obtained was further studied to determine its homogeneity.


Quantitative assay of sulphinpyrazone in plasma and urine by high-performance liquid chromatography.

A method for the quantitative determination of sulphinpyrazone in plasma and urine is described. The drug is extracted from the acidified aqueous phase with 1-chlorobutane-ethylene dichloride (4:1) and separated from its metabolites by high-performance liquid chromatography on 5-mum LiChrosorb using dichloromethane-ethanol-water-acetic acid (79.1:19:1.9:0.002) as the mobile phase. The sensitivity limit is 0,2mug/ml using a 1-ml sample. Examples of applications are given.


Determination of pethidine in plasma by electron capture gas chromatography after reaction with trichloroethyl chloroformate.

Pethidine (meperidine) is determined in plasma by electron capture gas chromatography after derivatization with trichloroethyl chloroformate. The analytical procedure involves extraction of pethidine and the internal standard from plasma and their separation from metabolites by partition chromatography. After purification of the eluate, the derivatization is accomplished with trichloroethyl chloroformate in the presence of anhydrous sodium carbonate. The reaction mixture is further purified with methanolic alkali before gas chromatographic analysis. Optimum conditions for extraction and derivatization, as well as the sensitivity and selectivity of the method are discussed. Owing to the high sensitivity the pethidine levels are determined in 0.1 ml of plasma. The smallest amount of pethidine determined by the method was 100 ng/ml. The relative standard deviation at the 50-ng level of pethidine added to 0.1 ml of plasma was 5.8%(n =8).


A rapid gas chromatographic determination of thiamphenicol in plasma and amniotic fluid.

A rapid gas chromatographic method for the determination of thiamphenicol in plasma and amniotic fluid is described. The antibiotic is extracted from biological fluids with ethyl acetate and, after concentration of the extract, the trimethylsilyl derivative of the drug is determined by electron-capture gas chromatography using a 63Ni detector. After the intravenous administration of a single dose of 500 mg of thiamphenicol during the first stage of spontaneous labour to clinically normal gravidae at term, transmission of the drug across the placenta was demonstrated by a combination of gas chromatography and mass spectrometry.


Improved theophylline serum analysis by an appropriate internal standard for gas chromatography.

A gas chromatographic method is presented for the measurement of theophylline in serum. To serum samples containing the drug the internal standard, 3-isobutyl-l-methylxanthine, was added and the serum was saturated with ammonium carbonate. A mixture of isopropanol-chloroform (5:95) was used for extraction. The organic phase was filtered and evaporated. The residue, dissolved in chloroform, was extracted with sodium hydroxide. The basic solution was acidified, washed with hexane and reextracted with isopropanol-chloroform. The organic phase was dried with anhydrous sodium sulphate before evaporation. The sample was derivatized with n-Butyl-8 reagent. 85% of theophylline was recovered by extraction. 3-Isobutyl-l-methylxanthine was recovered with the same efficiency as theophylline and gas chromatographed well. The standard curve was linear between 1.0 and 50.0 mug/ml theophylline. No interference was encountered from normal serum constituents or methylxanthines such as caffeine, theobromine, or 3-methylxanthine. Serum samples were stared in the refrigerator for two weeks without significant loss of drug. The precision and accuracy of the method were good.


Analysis of trace pollutants in the air by means of cryogenic gas chromatography.

The utilization of a laboratory-constructed programmable, cryogenic gas chromatograph (KEDBOR1OIR1) for use in air pollution studies is presented. The instrument (J. Chromatogr., 89(1974) 1) is modular in design and incorporates many commercially available components as well as a few "scratch-built" parts. A temperature control range of --100 degrees C to plus 300 degrees C, with five programmable rates, is possible using this particular instrument. The instrument is capable of dual-column and dual-detector operation. Data have been gathered from laboratory-prepared samples as well as from samples obtained from an air pollution study in the Philadelphia area. Small amounts (ppm or less) of the gaseous hydrocarbons and the common inorganic gases (NOx,SOx,CO, CO2, H2S, COS) are detected and quantitated. Calibration curves for each gaseous component have been constructed and the analyzed samples compared to them for quantitative data. Data and information from the use of several different columns, sampling sites and their locations are presented. Experimental data agreed favorably with the current findings and discussions of air pollution problems.


Fatty acids. VII. Gas-liquid chromatographic properties of all dimethylene interrupted methyl trans,trans-octadecadienoates.

All the dimethylene interrupted trans,trans-octadecadienoic acids were synthesised by lithium metal-ammonia reduction of the corresponding octadecadiynoic acids, except for the detla2t,6t isomer, which was obtained by the isomerisation of the delta2c,6c isomer. The gas-liquid chromatographic behaviour of the methyl esters was studied on polar [Carbowax 20M, FFAP, DEGA, DEGS, Silar 10C (recently renamed as Apolar 10) and SP 2330], semi-polar (XE-60), and non-polar (SE-30, OV101 and Apiezon L) stationary phases. The equivalent chain length of each isomer is recorded (including the delta2t,6c isomer) and the possibility of separation of these isomers is discussed.


Minor components of cannabis resin. VI. Mass spectrometric data and gas chromatographic retention times of components eluted after cannabinol.

Minor components of cannabis resin with longer retention times than that of cannabinol have been analyzed by use of a combined gas chromatograph-mass spectrometer-computer system. The presence of 30 such components has been detected. The data obtained indicate that some of the components are hydroxy derivatives of cannabinoids related to olivetol.


[Separation by high-performance liquid chromatography of phenylthiohydantoin derivatives of amino acids released by Edman degradation (author's transl)].

The separation by high-performance liquid chromatography of seventeen phenylthiohydantoin derivatives of amino acids released after Edman degradation of proteins is described. Sixteen phenylthiohydantoin derivatives of amino acids are differentiated within 40 min by liquid-liquid partition on a column packed with Micropak CN (moderately polar alkyl nitrile phase bonded on 10mum porous silica microparticles) and gradient elution with hexane=methylene chloride-isopropanol mixtures.


Determination of warfarin in animal relicta and feedingstuffs by  high-pressure liquid chromatography with confirmation of identity by mass spectrometry.

The determination of warfarin in liver, blood, urine and feedingstuffs by high-pressure liquid chromatography (HPLC) is described. Clean-up is simple and the lower limit of determination is about 0.025 ppm. Recoveries from liver are about 85% over the range 0.025-1.0 ppm; recoveries from blood range from about 67 to 90%. Chemical ionisation mass spectrometry can be used to confirm identity and, by specific ion monitoring, to detect warfarin in HPLC eluates at levels below the sensitivity of the HPLC detector.


Fluorogenic labeling of organophosphate pesticides with dansyl chloride. Application to residue analysis by high-pressure liquid chromatography and thin-layer chromatography.

The analysis of some organophosphorus pesticides by fluorogenic labeling with dansyl chloride (5-dimethylaminonaphthalene--l-sulfonyl chloride) was investigated. The pesticides were hydrolysed in sodium hydroxide to the corresponding phenols. The reaction of dansyl chloride with the phenols was accomplished in a two-phase system. The resulting fluorescent derivatives were separated and analysed quantitatively by in situ thin-layer chromatography (TLC) and high-pressure liquid chromatography (HPLC). As little as 10-25 ng/spot of pesticide was detected by both TLC and HPLC.


Reversed-phase ion-pair partition chromatography of phenylacetic, mandelic and pyridinecarboxylic acid derivatives.

Phenylacetic, mandelic and pyridinecarboxylic acids of physiological interest have been separated by ion-pair partition chromatography with 1-pentanol as stationary phase and tetrabutylammonium as counter ion in the aqueous mobile phase. The stability of the chromatographic system is very high and the support is spontaneously re-coated with stationary phase. Untreated plasma samples can be injected in relatively large volumes without serious loss of separating efficiency. A venting system was found efficiently to reduce disturbing early peaks on injection of biological samples.


Rapid and sensitive high-resolution procedure for digitalis glycoside analysis by derivatization liquid chromatography.

The separation and quantitative determination of digitalis glycosides by high performance liquid chromatography following derivatization with 4-nitrobenzoylchloride (4-NBC1) is described. The compounds of primary interest were the digitalis glycosides and aglycones of the pharmaceutically important A, B and C series, The derivatization step results in higher extinction values at a more favourable wavelength (260 nm), which permits the use of low-cost ultraviolet detectors. Detection limits are below 20 ng/ml for all of the glycosides tested. The chromatographic properties are also improved by reducing the polarity without a decrease in selectivity. The use of low-polarity and low-viscosity solvent systems on silica gel adsorbents permits rapid isocratic separations of complex mixtures as they usually occur in pharmaceutical products and extracts. The quantitative potential of this method was demonstrated by analyzing ampoule solutions containing desacetyl lanatoside C as the active compound. The active substance, by-products and degradation products were determined down to 0.1% of the total glycoside concentration in one ampoule.


Ion-pair partition chromatography in the analysis of drugs and biogenic substances in plasma and urine.

Liquid-liquid chromatography based on the ion-pair partition technique gives separation systems of high efficiency when silica micro-particles are used as the support for the stationary phase. With 10-mum particles, plate heights of the order of 40-70 mum have been achieved with a linear velocity of 0.25 cm/sec. The retention in ion-pair partition systems is determined by the nature and concentration of the counter ion, and the properties of the mobile phase also have a major influence. It is often possible to predict the selectivity, and this can be controlled by varying the composition of the mobile phase. This paper describes the application of ion-pair partition chromatography to the bioanalysis of drugs, drug metabolites and biogenic substances. Typical counter ions in the stationary phase were methanesulphonate and perchlorate for ammonium compounds and tetrabutylammonium for the separation of organic anions. Determinations by liquid chromatography were demonstrated for quinidine and dihydroquinidine, metanephrine and normetanephrine and for imipramine and its demethyl metabolite in plasma. A quaternary ammonium compound, QX-572, was determined in urine and chromatograms are shown for the isolation of indoleacetic and hydroxyindoleacetic acid in urine. The methods have been used in routine analysis. Ultraviolet detection has permitted the determination of highly absorbing compounds down to the 10-ng level in plasma and urine.


Identification of drugs using a gas chromatography-mass spectrometry system equipped with electron impact-chemical ionization and electron impact-field ionizationfield desorption combination sources.

In a case of toxicological analysis by gas chromatography (GC)-mass spectrometry-data system, chemical ionization (CI), field ionization (FI) and electron impact data are shown to lead rapidly to assignments for all significant GC peaks. Valuable data include not only full spectra in the three ionization modes, but also exact mass measurements in the FI or CI mode. Such measurements, obtained by a dynamic peak-matching technique, lead to the elemental composition of the compounds of interest. This knowledge makes the assignment of key GC peaks unequivocal and provides an extremely high level of confidence regarding the identity of whole metabolite series. It is also shown that the nature of the FI information is very similar to that obtained from CI data.


Organic micropollutants in air and water. Sampling, gas chromatographic-mass spectrometric analysis and computer identification.

Organic micropollutants are sampled by dynamic enrichment on a porous polymer column and subsequently thermally eluted in a flow of helium. The eluted compounds enter gas chromatograph inlet and then pass into two parallel glass capillary columns with different stationary phases, in which they are separated. The separated compounds are detected by gas chromatographic (GC) detectors and by a mass spectrometer that is connected to one or other of the two capillary columns by "heart cutting" systems. The GC and mass spectrometric (MS) signals are fed via interfaces into a minicomputer which controls the MS scan and performs data acquisition, reduction and treatment on-line and off-line. The resulting GC and MS data are displayed on a line printer or a visual display unit. The minicomputer is connected by a telephone line to an IBM 370/165 computer, where a library search system has been implemented. Some difficulties encountered, data on the sampling recovery of model compounds and the identification of compounds in air and water samples by GC-MS data and library searches are discussed.


New derivatives for the analysis of sphingosine long-chain bases by gas-liquid chromatography-mass spectrometry.

Cyclic derivatives formed by reaction of sphingosines with methane-, n-butane- and benzeneboronic acid have been examined by gas-liquid chromatography (GLC) and by combined GLC-mass spectrometry (MS). Analogous compounds have also been studied, in which the amino group has been protected, for example as an acetone Schiff base or N,N-dimethylaminomethylene derivative. Phytosphingosine (4D-hydroxysphinganine) yielded bis-alkaneboronates. Most of the derivatives were satisfactory for GLC. Molecular ions were apparent (1-100% relative abundance) in all electron impact mass spectra, and and (as [M+1](+)ions) were the base peaks in isobutane chemical ionisation mass spectra.


Determination of phenobarbital in human saliva by gas chromatography with electron-capture detection.

A gas chromatographic method for the determination of phenobarbital in saliva has been developed. Phenobarbital is converted into its bispentafluorobenzyl derivative by extractive alkylation at pH 9 with 0.1 M tetrabutylammonium ion as extracting agent and 0.1 M pentafluorobenzyl bromide as alkylating reagent in methylene chloride. A reaction time of 20 min is required. Quantitation is effected by electorn-capture detection in a gas chromatograph equipped with a pre-column venting system for removal of methylene chloride and pentafluorobenzyl bromide. This procedure allows the direct introduction of the reaction mixture into the gas chromatograph. A 60-ng amount of phenobarbital in 100 mul of human saliva can be determined with a precision of 1.9% (S.D.) and a recovery of 93%.


Levels of free and protein-bound progesterone in plasma during late pregnancy.

Using a filter method, levels of free (unbound) and protein-bound progesterone in blood samples were measured serially from the 23rd week of pregnancy until delivery in 16 healthy women. In addition, total estrogen and progesterone concentrations were determined by radioimmunoassay. The levels of both free and total progesterone increased steadily until the end of pregnancy. Free progesterone increased with advancing pregnancy more in proportion to the total progesterone, as it rose from 6% (of total) at week 24 to 13% at week 40. Both free and total progesterone decreased markedly very soon (2 h) after delivery. However, the corresponding decrease in the level of free progesterone was considerably less, with the result that it rose to 19% of the total, the greatest proportion of free progesterone observed at any time. The levels of both total estrogen and progesterone in plasma increased with advancing pregnancy, and at no time, prior to delivery, was there a significant fall in progesterone or an abrupt rise in estrogen.


Identification of corticosteroid-binding globulin in human milk: measurement with a filter disk assay.

We have studied the concentration and properties of a protein which binds cortisol in human milk in samples obtained from women during the first 100 days after delivery. A filter disk assay was developed both for the measurement of plasma corticosteroid-binding globulin (CBG) and for the cortisol-binding protein in milk. The concentration of CBG in milk, expressed as its capacity to bind cortisol, is highest on the day of delivery, ca, 0.80 mug/dl, falls over the next 10 days to ca. 0.25 mug/dl, and remains at that level thereafter. If the concentration of CBG is expressed relative to the concentration of serum albumin in milk, it increases from day 1 to day 3 and then remains constant. A detailed comparison of CBG derived from milk and plasma showed that the two proteins co-migrated on Sephadex, sucrose gradient ultracentrifugation, and polyacrylamide gel electrophoresis. The two proteins had the same affinity for cotrisol, progesterone, 17-OH-progesterone, and dexamethasone. Furthermore, the binding activity of CBG in milk was neutralized with anti-CBG antibodies raised against CBG isolated from plasma. Unlike CBG, the concentration of cortisol in milk, 0.8-3.5 mug/dl, showed no systematic variation as a function of the postpartum day on which the sample was obtained.


Intratesticular site of aromatization in the human.

To determine the intratesticular site of aromatization, homogenates of separated seminiferous tubules and intact tissue from human testes were incubated with [3H] androstenedione or [3H] testosterone. [3H] Estrogens were isolated and identified, and the amounts synthesized were expressed as pmol/mg protein incubated. In testicular tissue from the three adult subjects investigated, the total estrogen per mg protein was 1.5-2.7 times greater in intact tissue than in isolated seminiferous tubules. This suggests that the major site of aromatization in human testes is the interstitial tissue. Estradiol was by far the major estrogenic product. No differences were observed in the amount of estrogens synthesized whether the substrate was androstenedione or testosterone.


The insulinotropic effect of endogenous gastric inhibitory polypeptide in normal subjects.

Intravenously administered porcine GIP is insulinotropic in man. This study was designed to investigate the effects of simultaneous fat ingestion, a potent stimulus for GIP release, and intravenous glucose infusion upon endogenous serum GIP and insulin concentrations in normal subjects. Seven normal volunteers were studied on three separate occasions following: a) the ingestion of 67 grams of emulsified corn oil, b) constant intravenous infusion of glucose, and c) simultaneous administration of corn oil and glucose as in parts (a) and (b) of the study. Serum glucose, insulin (IRI), and GIP concentrations were measured at intervals between 15 and 180 minutes following each stimulus. With corn oil, mean serum GIP concentrations increased from a fasting level of 290 +/- 40 (SE) pg/ml to 1936 +/- 402 pg/ml at 60 minutes without a significant change in serum IRI or glucose concentrations. The infusion of intravenous glucose alone was associated with no rise in serum GIP levels despite a substantial increase in serum IRI and glucose concentrations. With the combined stimuli, mean serum GIP increased less (P is less than .05) between 30 and 90 minutes, and total integrated incremental GIP was significantly less (P is less than .025) than that after corn oil ingestion alone. Following the combined stimuli, incremental insulin levels were higher (P is less than .05) between 15 and 90 minutes, total integrated incremental insulin was greater (P is less than .025), and glucose homeostasis was significantly enhanced (P is less than .05) at 120 and 180 minutes compared with the effects on insulin of glucose infusion alone. We conclude that the potentiation of glucose-stimulated insulin secretion induced by the ingestion of fat is associated with serum GIP levels that are within the insulinotropic range. The augmented secretion of insulin may be mediated partially or completely by endogenous GIP. The lower serum GIP concentrations observed following the combined stimuli suggest a feedback inhibition of GIP release which is perhaps mediated by insulin.


Comparison of serum pituitary thyrotropin and chorionic gonadotropin concentrations throughout pregnancy.

Concentrations of human pituitary thyrotropin (hTSH) and human chorionic gonadotropin (hCG) were measured by specific radioimmunoassays in serum samples obtained from 243 pregnant women. The hTSH levels demonstrated suppression during the sceond through the fourth months, followed by a linear rise to non-pregnant control levels throughout the remainder of gestation. At the time that the hCG levels were at their lowest concentration. However, a reciprocal relationship between the hCG and hTSH concentrations in individual samples was not found. The inverse relationship between mean levels of hTSH and hCG during early pregnancy suggest that the intrinsic thyroid-stimulating activity of hCG may be important in the control of thyroid function during the first trimester. The failure to confirm this relationship in individual serum samples indicates that other factors also influence maternal thyroid homeostasis during early gestation.


Effects of oral therapy with calcium and vitamin D in primary osteoporosis.

Eighteen patients (17 women and 1 man) with primary osteoporosis were divided into two groups of 9 patients each. Group A received 2.0 to 2.5 g of calcium and 400 units of vitamin D per day orally and was studied before and after short-term (3 to 4 months) treatment; group B received 1.5 to 2.0 g of calcium per day and 50,000 units of vitamin D twice weekly and was studied before, after short-term, and after long-term (1 year) treatment. In group A there was a decrease (P is less than 0.01) in bone-resorbing surfaces (microradiography of bone biopsy samples) after short-term treatment. In group B there was a decrease (P is less than 0.01) in bone-forming and bone-resorbing surfaces after both short-tern and long-term treatment. Fasting-state (morning) serum immunoreactive parathyroid hormone (iPTH) concentrations decreased after short-term treatment (combined data of groups A and B) and after long-term treatment (group B). We conclude that the principal effect of the oral calcium and vitamin D therapy in primary osteoporosis is to decrease bone turnover. The most probable mechanism for this effect on bone is a partial inhibition of PTH secretion.


Growth hormone and cortisol responses to psychological stress: comparison of normal and neurotic subjects.

The mirror drawing test (MDT) was performed to induce acute psychological stress in 9 normal controls and 10 neurotic subjects. Plasma growth hormone (GH) and cortisol were determined serially before, during, and after the test. In controls the MDT caused no significant change in plasma GH level, while in neurotics plasma GH increased progressively following the test. The increase of cortisol also tended to be greater in neurotics as a group, but there was considerable overlap in individual responses. The maximum increments of GH in neurotics correlated inversely with those of cortisol. The results indicate: 1) effective psychological coping mechanisms operate in normal man to keep the hormonal response minimum. 2) GH response is a more adequate indicator than cortisol response to psychological stress in neurotics. 3) GH and cortisol may have different psychological correlates in neurotics.


Serum neurophysins during passive assumption of the erect posture in men and during pregnancy: effect of syncope.

A slight but reproducible increase in serum total immunoreactive neurophysin levels (IRN) occurred 30 minutes following passive assumption of the erect posture (tilt test) in 12 men (17%, 2 P is less than .02) and in 6 pregnant women (20%, 2P=NS) who showed normal cardiovascular adaptation during the test and did not suffer syncope. The increase was much more marked in 4 men in whom there was a fall in blood pressure and syncope in assuming the upright posture. An increase of twice the basal level was also found in a pregnant women who experienced syncope, although she was maintained horizontal. Our results show that it is important to ensure the absence of these intercurrent phenomena in the correct interpretation of dynamic clinical tests of neurohypophysial function.


The effect of rate and dose of glucose infusion on the acute insulin response in man.

Two types of studies have been done to determine the importance of the rate of plasma glucose concentration change to the magnitude of the acute insulin response following an intravenous glucose injection in normal men. When an identical amount of glucose (20 g) was given at varying infusion rates (1.67 g/min to 66.7 g/min), the magnitude of the acute insulin response was found to be proportional to the rate. When various doses (5 g to 20 g) were given at the identical rate (1.67 g/min) the acute insulin response did not change. When 5 g of glucose was given in 0.3 and 3 minutes, a sub-maximal acute insulin response resulted which was still rate-dependent (delta peak IRI=35.5 +/- 5 at 5 g/0.3 minutes, 21.8 +/- 3 at 5 g/3 minutes). We have concluded that the human islet acts as a sensor for both the concentration of plasma glucose and the rate of change in plasma glucose. Islet perception of both these phenomena are critical factors in the determination of the magnitude of the acute insulin response.


Similar serum IgM concentrations in Greek endemic goiter and control populations: failure to confirm previous experience.

Circulating immunoglobulin M (IgM) concentrations were determined in 47 nontoxic goiter patients from four Greek endemic goiter areas, and in 13 patients from Athens, a non-goitrous area; and compared with 38 control non-goitrous subjects from the same goiter regions, and 23 more controls from Athens. The values in both goitrous and non-goitrous groups were indistinguishable. Current techniques for single radial immunodiffusion were employed. The results are expressed in standardized international units/ml serum, instead of the formerly used mg/dl. The present findings are in disagreement with the earlier observation from this laboratory that 40 per cent of goitrous patients had elevated IgM values compared with 10 per cent of control subjects.


The pituitary-thyroid axis in adults with phenylketonuria.

Serum thyroxine and triiodothyronine levels in 15 adult phenylketonuric patients on an unrestricted diet were normal despite reduced circulating tyrosine levels. Serum thyrotropin levels were normal in the basal state or in response to thyrotropin-releasing hormone in selected patients tested. These results support and extend previous observations of normal thyroid function in phenylketonuria.


Growth hormone radiologand assay unresponsive to human prolactin.

A specific and sensitive radioligand assay for growth hormone with female rat liver plasma membranes is presented. Growth hormones of different species are able to displace labelled human growth hormone from membrane binding sites with parallel standard curves. Human prolactin V-L-S is not equal to 1 and the international human prolactin standard MRC 71/222 do not affect the assay. Human prolactin preparations with different growth hormone content displace human growth hormone tracer only to the same extent as they contain growth hormone when measured by radioimmunoassay.


Growth hormone refractory interval to levodopa stimulation.

The GH response to repeat l-dopa stimulation was studied in three phases. In phase I and phase II, 16 normal adults divided into four groups were restimulated at 3, 4, 5, and 6 hours with 500 mg l-dopa and 1000 mg l-dopa, respectively. No response could be elicited at 3 hours and only at 6 hours (500 mg l-dopa) and 5 hours (1000 mg l-dopa) did the repeat responses return in magnitude to that of the initial. The period of decreased responsiveness to GH was terned the "refractory interval". In phase III, addition of an inhibitor of peripheral L-aromatic amino acid decarboxylase (50 mg MK-486) to the restimulation dose shortened but did not eliminate the refractoriness. Our results suggest that the refractory interval is not due to a peripherally located mechanism.


Persistence of antibody to hepatitis B surface antigen.

Sera from military personnel found to have antibodies to hepatitis B surface antigen (anti-HBS) in an epidemiological study of a hepatitis B outbreak were tested for persistence of that antibody 1 year later. Initially, 64% of the anti-HBS-positive sera reacted in passive hemagglutination tests with erythrocytes coated with hepatitis B surface antigen of both ayw and adw subtypes; the remaining sera reacted only with adw-coated erythrocytes (19%) or ayw-coated erythrocytes (17%). After 1 year, anti-HBS was detectable by passive hemagglutination tests in 87% of individuals with initial antibody to both subtypes but in only 41% and 16% (P less than 0.001) of those initially reacting only to adw- or ayw-coated erythrocytes, respectively. Seropositivity for anti-HBS correlated best with history of contact with jaundiced people (20.3%) and duty in Asia.


Clinical evaluation of the addition of gentamicin to commercially prepared mycological media.

A simple procedure is presented whereby an antibiotic solution can be added to prepared agar media for conversion to a selective medium to isolate fungi. Gentamicin solution was deposited onto slants of a variety of previously prepared agar media, allowed to diffuse overnight, and then the slants were inoculated with clinical specimens. Control media without gentamicin included a cycloheximide-chloramphenicol medium (CC), Sabouraud dextrose agar (SDA), and brain heart infusion agar (BHI). Of 75 specimens originating from the respiratory tract, the fungi isolated were predominantly yeast; 35, 39, and 43 were positive on CC, SDA, and SDA with gentamicin, respectively, incubated at 25 C. At 37 C, 32, 34, and 41 positive cultures were obtained with the same media, respectively. The same specimens, inoculated onto BHI with and without gentamicin, yielded 23 and 39 positive cultures, respectively. Of 90 specimens that were either urine, cutaneous, or mucocutaneous, the predominant flora again were yeasts, although on nine occasions dermatophytes were isolated. Positive cultures, 32, 34, and 41, were obtained with CC, SDA, and SDA containing gentamicin, respectively. Bacterial contamination was significantly reduced by the gentamicin, especially on BHI incubated at 37 C. None of the specimens was positive for systemically pathogenic fungi, other than species of Candida, Torulopsis, and Aspergillus. The effectiveness of varying concentrations of gentamicin was investigated by comparing growth of recently isolated bacteria. Of the bacterial isolates, 33% grew on CC, 16% grew on SDA containing gentamicin, 50 mug/ml, and 3% grew on SDA with a gentamicin concentration at 100 mug/ml. With BHI, 3% grew in the presence of 50 mug of gentamicin/ml and less than 1% grew at 100 mug of gentamicin/ml.


Purification of influenza virus with Arcton 113.

Arcton 113 has proved effective in the removal of host membrane fragments which cosediment with influenza virus during differential centrifugation. The virus appeared morphologically undamaged by the procedure and retained its infectivity, neuraminidase, and hemagglutinating activity. Pyrogenicity, however, was considerably reduced.


Hormone-fuel concentrations in anephric subjects. Effect of hemodialysis (with special reference to amino acids).

Arterial blood concentrations of insulin, glucagon, and various substrates were determined in six anephric subjects in the postabsorptive state and immediately after hemodialysis. Plasma glucose and serum insulin concentrations were normal, and declined during dialysis. Plasma glucagon was elevated and remained unchanged. There was moderate hypertriglyceridemia before dialysis, but this decreased significantly after administration of heparin just before the start of dialysis, and at the end of dialysis was lowered further into the normal range. Comparison of postabsorptive whole blood concentrations of amino acids with those in normal, healthy adults revealed striking differences. Glutamine, proline, citrulline, glycine and both 1- and 3-methyl-histidines were increased, while serine, glutamate, tyrosine, lysine, and branched-chain amino acids were decreased. The glycine/serine ratio was elevated to 300% and tyrosine/phenylalanine ratio was lowered to 60% of normal. To investigate the potential role of blood cells in amino acid transport, the distribution of individual amino acids in plasma and blood cell compartments was studied. Despite a markedly diminished blood cell mass (mean hematocrit, 20.6 +/- 1.4%), there was no significant decrease in the fraction of most amino acids present in the cell compartment, and this was explained by increases of several amino acids in cellular water. None were decreased. Furthermore, during dialysis, whole blood and plasma amino acids declined by approximately 30% and 40%, respectively, whereas no significant change was observed in the cell compartment. Alanine was the only amino acid whose concentration declined in the cells as well as in plasma. The results indicate (a) significant alterations in the concentrations of hormones and substrates in patients on chronic, intermittent hemodialysis; (b) removal of amino acids during hemodialysis, predominantly from the plasma compartment, with no significant change in cell content; and (c) a redistribution of amino acids in plasma and blood cell compartments with increased gradients of most of the amino acids per unit cell water, by mechanism(s) as yet undetermined.


Magnesium absorption in the human small intestine. Results in normal subjects, patients with chronic renal disease, and patients with absorptive hypercalciuria.

Magnesium absorption was studied in the normal human jejunum and ileum by in vivo intestinal perfusion, using test solutions containing from 0 to 20 mM Mg (as MgCl2). As luminal Mg concentration was increased, the rate of absorption in the jejunum rose progressively with a tendency towards saturation at the higher concentrations. The kinetics and rates of Mg absorption in the ileum were comparable to those in the jejunum, with the exception that at higher luminal concentrations the ileal absorptive process was fully saturated. Using test solutions containing various combinations of Ca and Mg, we found that Ca had little or no influence on Mg absorption, even through Mg depressed Ca absorption to a modest extent. Patients with end-stage renal disease, who had a reduced rate of Ca absorption (presumably due to deficiency of 1,25-dihydroxycholecalciferol) were found to have a severe depression of Mg absorption. On the other hand, patients with absorptive hypercalciuria and nephrolithiasis, who had an increased rate of Ca absorption, were found to absorb Mg normally. These results suggest that Mg absorption in the human is mediated by a transport process different from that which facilitates Ca absorption, and that normal Mg absorption may be dependent on vitamin D. Our results do not establish whether or not the normal intestine can absorb Mg against an electrochemical gradient.


Immune function of successfully treated lymphoma patients.

Immunologic function was evaluated in 12 patients with Hodgkin's disease and 5 patients with lymphocytic lymphoma who had been successfully treated with either chemotherapy, radiation therapy, or both of these modalities 3-42 mo previously. Only two of the patients were found to have total anergy to a battery of six recall skin test antigens and all were responsive to skin testing with phytohemagglutinin. However, 10 of 16 patients were unable to develop delayed cutaneous hypersensitivity to either of the neoantigens dinitrochlorobenzene or keyhole limpet hemocyanin. Four other patients developed reactivity to only one of these neoantigens for a total of 14 of 16 (88%) of the patients demonstrating some impairment in neoantigen response. Total lymphocyte, T-lymphocyte, B-lymphocyte, and null cell numbers, as well as serum immunoglobulins were quantitatively normal. Monocyte numbers, chemotaxis, and Fc receptor activity were normal. Monocyte staphylocidal activity at 60 min was modestly depressed and candidacidal activity was depressed in those receiving both chemotherapy and radiation therapy. Spontaneous (unstimulated) lymphocyte [3H]thymidine incorporation was low in the patients as a group and lymphoblastic transformation to specific antigens was impaired in 11 of 17 patients who had positive skin test reactions to the same antigen. Highly significant suppression of lymphoblastic transformation was noted after stimulation by the mitogens phytohemagglutinin, pokeweed, and concanavalin-A. The greatest impairment of mitogen response was seen in those patients receiving both chemotherapy and radiation therapy. These data demonstrate specific impairments of neoantigen processing, lymphocyte function, and to a lesser extent monocyte function in successfully treated patients with lymphoma. These impairments may contribute to the increased incidence of infections and second primary malignancies in these patients.


Proximal bicarbonate reabsorption during Ringer and albumin infusions in the rat.

Several studies have clearly shown that extracellular volume expansion is associated with suppression of whole kidney bicarbonate reabsorption, although little is known concerning the single nephron correlates of this response. More recently, attention has also been focussed on bicarbonate transport in attempts to identify a possible role for this ion in enhancing the rate of net fluid efflux by proximal tubules. To further explore proximal tubular bicarbonate handling in the rat, we carried out recollection micropuncture studies to assess the effects of infusions of modified Ringer or salt-poor hyperoncotic human albumin. With stable levels of arterial PCO2, plasma [HCO3-] or plasma [K+], marked suppression of fractional HCO3- reabsorption occurred: during Ringer infusion fractional reabsorption fell by 31% (P less than 0.001) while during albumin infusion a decrease of 20% (P less than 0.001) was observed. Despite this, absolute net HCO3- reabsorptive rates did not change significantly. Simple and partial correlation analysis of single tubular responses revealed strong linkage effects between changes in absolute net reabsorptive rates for HCO3- and H2O in both types of infusion; the partial r was 0.91 (P less than 0.001) and 0.94 (P less than 0.001) during Ringer and albumin infusions, respectively. We conclude that under these free-flow conditions, Ringer and albumin infusions do not suppress absolute net HCO3- reabsorption by proximal tubules, and that strongly linked changes in absolute HCO3- and H2O fluxes are characteristic of both protocols.


Cellular basis of insulin insensitivity in large rat adipocytes.

The marked stimulatory effect of insulin on the conversion of 20 mM D-[6-14C]glucose to CO2, glyceride-glycerol, and fatty acid observed in small rat adipocytes was greatly diminished in large cells from older rats. Similarly, total glucose utilization as estimated by summing the total metabolites accumulated intracellularly plus the release of labeled CO2 and lactate was substantially lower in large cells in the presence of insulin and 5 mM labeled glucose. However, under conditions of 0.2 mM medium glucose where transport of the hexose into adipocytes is relatively more rate-limiting for subsequent metabolism, large cells actually utilized slightly greater total amounts of glucose than small cells in the presence of insulin. Increments of total glucose utilization due to both submaximal and maximal doses of insulin were similar in large and small cells incubated with a low glucose concentration. Under these conditions, conversion of labeled glucose to CO2 and fatty acid in response to insulin was somewhat diminished in large cells, while conversion to glyceride-glycerol was enhanced. The activity of the D-glucose transport system in large and small cells was estimated by monitoring initial rates and small cells was estimated by monitoring initial rates of 3-O-[3H]methylglucose uptake by a rapid filtration method. Transport system activity on a per cell basis was actually severalfold higher in large adipocytes in the basal state as well as in the presence of submaximal and maximal concentrations of insulin compared to small cells. However, the percent stimulation by insulin was less in the large cells. Uptake of 2-deoxyglucose under basal conditions and in response to insulin was also higher in large cells compared to small cells. Analysis of the accumulated label in extracts from fat cells incubated with D-[14C]deoxyglucose revealed the presence of free deoxyglucose, deoxyglucose-6-phosphate, and 6-phosphodeoxygluconate. The levels of these metabolites were significantly higher in large cells compared to small cells indicating hexokinase activity appears not to account for the defective glucose utilization in large cells at high glucose concentrations. It is concluded that (a) possible defects in insulin receptor components, the D-glucose transport system, and the coupling mechanism which links these entities do not significantly contribute to the apparent insulin-insensitivity of large fat cells and (b) the principal cellular defect which confers this blunted insulin response to large rat adipocytes involves one or more intracellular enzymes involved in glucose metabolism.


Comparison of effects of 1 alpha-hydroxy-vitamin D3 and 1,25-dihydroxy-vitamin D3 in man.

The effects of short-term treatment with 1,25-dihydroxy-vitamin D3 [1,25(0H)2D3] or 1 alpha-hydroxy-vitamin D3 [1 alpha(OH)D3] on intestinal absorption of 47Ca were compared in 41 experiments in normals and 72 experiments in patients with chronic renal failure. 11 patients were studied a second time after treatment for 2-5 mo. Doses varied from 0.14 to 5.4 mug/day to establish dose-response relationships. Urinary calcium was monitored in normal subjects, nine of whom received a constant calcium intake on a metabolic unit. There was an increase in intestinal absorption of 47Ca and urinary calcium in normals receiving 1,25 (OH)2D3, 0.14 mug/day or greater, and 0.28 mug/day or greater augmented intestinal absorption of 47Ca in chronic renal failure. In contrast, 2.6 mug/day of 1 alpha (OH) D3 was required to increase intestinal absorption of 47Ca in both groups. The increase in urinary calcium to maximal levels was delayed during treatment with 1 alpha (OH) D3, 5-10 days vs. 2-5 days with 1,25 (OH)2D3. Moreover, half times for urinary calcium to decrease to pretreatment levels after stopping treatment were greater after 1 alpha-(OH) D3 (1.5-2.7 days) than 1,25(OH)2D3 (1.1-2.0 days). With long-term administration there was a progressive increase in intestinal absorption of 47Ca in the patients receiving 1 alpha (OH)D3; this was not observed with 1,25(OH)2D3. The pharmacologic differences between 1 alpha(OH) D3 and 1,25(OH)2D3 may be explained by the requirement for 25-hydroxylation of 1alpha(OH) D3 before biologic effects occur; at low doses (less than 1 mug/day), 1 alpha(OH) D3 competes with vitamin D3 for 25-hydroxylation. With prolonged treatment or larger doses (greater than 2 mug/day),, 1alpha(OH) D3 could accumulate and then be hydroxylated resulting in production of higher levels of 1,25(OH)2D3.