Progesterone-releasing vaginal rings for use in postpartum contraception. II. Pharmacokinetic profiles in women.

Vaginal rings releasing progesterone with 3 different initial release rates (5, 8 and 20 mg/day) were used by 11, 10 and 10 women, respectively. The period of insertion was 90 days. The 5 and 8 mg/day rings consisted of a core loaded with progesterone, the 20 mg/day ring contained progesterone homogeneously distributed throughout the mass of the ring. Notwithstanding these differences, the total progesterone levels (areas under curve) were directly related to the release rates. So were the rates of decrease of progesterone levels during the 90 days of insertion of the ring. They were 25, 31 and 47% for the rings releasing 5, 8 and 20 mg/day, respectively.


Postpartum IUDS: keys for success.

Intrauterine device (IUD) insertion is convenient and efficient in the postplacental and immediate postpartum periods. Insertion at these times is demonstrably safe, having a low incidence of infection, few bleeding problems, and low perforation rates. IUD expulsion rates can vary widely, and are a function of timing of insertion, type of IUD, and insertion technique. When a copper T device is inserted postplacentally or immediately postpartum by an experienced and trained clinician, expulsion rates of about 7-15 per 100 users at six months can be expected. Women must be told how to detect expulsions and instructed to return for reinsertion or for another method. Most investigators emphasize that high fundal IUD placement will reduce the expulsion rate. Unplanned pregnancy rates for postplacental IUD insertion range from 2.0-2.8 per 100 users at 24 months when using modern copper IUDs, correct insertion technique, careful postinsertion instructions and good follow-up. Postplacental insertions are performed manually or with a ring forceps. Immediate postpartum insertions (10 minutes to 48 hours after delivery) are performed with the ring forceps.


Accuracy of recall of use of an intrauterine device.

Within a case-control study of the relationship between oral contraceptives and breast cancer, information on other contraceptive practices, including use of an intrauterine device (IUD) was obtained through interviews of study subjects and from the records of gynaecologists. Information from these two sources was compared for 239 women who had ever used an IUD. The results showed that agreement on total duration, number of IUD episodes, and time since first and time since last IUD use was excellent. As approximately 75% of IUDs used were unknown, agreement on brands could not be investigated. Studies investigating the effects of individual types of IUDs should use physician records as an additional source of information.


GnRH antagonists suppress prolactin release in non-human primates.

GnRH antagonists, such as Antide, are being evaluated for potential contraceptive applications. Although their contraceptive efficacy clearly results from their rapid inhibitory effects on gonadotropin release, there remains the possibility of other incidental effects. Under certain physiological conditions, the release of prolactin (Prl) appears to be temporally related to the secretion of luteinizing hormone (LH) and hence by inference to the secretion of GnRH. Here, we examined the effects of the GnRH antagonist Antide on the release of LH and Prl. Under agonadal conditions, a remarkable concordance was seen between LH and Prl pulses with up to 100% of pulses being coincident. Administration of Antide resulted in a rapid parallel decline in both LH and Prl with LH levels falling by 50% within 2 h and Prl levels falling by 30-40%. At this dose of Antide (1.0 mg/kg, sc), pulsatile release of LH and Prl continued albeit at a much reduced amplitude. The administration of a bolus of exogenous GnRH in the face of GnRHant-induced suppression resulted in prompt release of LH and Prl in all 3 monkeys. Since Antide inhibits the release of LH and Prl in a parallel fashion, and GnRH re-stimulates the release of both hormones in a parallel fashion, we conclude that the synchronous pulsatile release of LH and Prl observed in the agonadal monkey is due to a direct action of GnRH. What this action is for Prl release, and how it relates to the control of dopamine or other neuroendocrine mechanisms normally controlling the release of Prl remains unclear. It also remains to be seen whether this GnRH antagonist-induced suppression of Prl will have physiologic significance.


Interference with ovulation and luteal function by human ovarian follicular fluid peptide in bonnet monkeys, Macaca radiata.

Partially purified human ovarian follicular fluid peptide (hGF2) was administered during follicular phase in 5 bonnet monkeys. In control as well as hGF2-injected animals, ovulation was synchronized by treatment with FSH, Pergonal and hCG. All the 5 control bonnet monkeys showed plasma estradiol peak followed by increased progesterone levels. In 4 out of 5 hGF2-injected animals, plasma progesterone levels were drastically reduced. Plasma estradiol levels were decreased only in 3 animals in which amenorrhea was observed. These data reveal that hGF2 injection disrupted ovarian function in bonnet monkeys.


Facial psoriasis.

The face has been cited as being the least affected body surface in patients with psoriasis. It also has been reported that psoriasis of the face is more prevalent in children than in adults, and when it does occur, at any age, the face is never the only body part involved. In fact, face involvement may reflect a high degree of severity of psoriasis.


Eruptive xanthoma.

We recently had occasion to diagnose eruptive xanthoma. The significance of this cutaneous finding is that it is indicative of an underlying hypertriglyceridemic state. Appropriate dietary changes, correction of secondary factors, along with the addition of antihyperlipidemic drugs as required, will lower the plasma triglyceride level and allow the xanthomatous lesions to resolve.


Multiple epidermoid cysts in a renal transplant recipient taking cyclosporine A.

A forty-two-year-old male recipient of a cadaver renal transplant showed multiple nodulocystic lesions on his back and lateral aspects of his neck four months after beginning immunosuppressive therapy with cyclosporine A and prednisone. Results of histopathologic studies revealed that they were epidermoid infundibular cysts. We note the relationship between this clinical appearance and cyclosporine A, as well as this agent's cutaneous side effects.


Folic acid and vitamin B12 in vitiligo: a nutritional approach.

When compared with the normal population, patients with vitiligo often showed diminished blood levels of folic acid. In a group of fifteen patients with vitiligo, folic acid levels were below normal in the serum of eleven patients, in the whole blood of five patients, and in the erythrocytes of six patients. Vitamin B12 serum levels were below normal in five of the fifteen patients. Ascorbic acid plasma levels were also lowered in four of the patients. In eight patients prolonged oral administration of folic acid with simultaneous parenteral treatment with vitamin B12 and oral ascorbic acid was followed by definite repigmentation without side effects.


Systemic amyloidosis secondary to chronic leg ulcers.

Chronic leg ulcers due to any cause are almost invariably associated with an inflammatory process. As with any long-standing inflammation, leg ulcers may be complicated by systemic amyloidosis, which occurs in rheumatoid arthritis, cystic fibrosis, tuberculosis, and other disorders. There are, however, very few reports on the association between these two conditions. We report a patient with severe leg ulcers of twenty years' duration in whom reactive systemic amyloidosis presented as a nephrotic syndrome.


Calcification of the auricular cartilage: a case report and literature review.

We report a case of auricular calcification in an elderly man with a history of frostbite and normal serum calcium levels. The causes of calcification of the cartilage of the external ear are discussed.


Treatment-resistant psoriasis due to a mastectomy sleeve: an extensive Koebner response.

The Koebner or isomorphic response refers to the appearance of a dermatosis at sites of trauma. This process was first described by Heinrich Koebner in a man with psoriatic plaques in areas of trauma. Many types of trauma are capable of producing koebnerization. We report a case of extensive koebnerization in response to the wearing of a mastectomy sleeve, worn to reduce lymphedema. Both the chronic pressure produced by the device and the trauma of applying the sleeve produced the necessary dermal and epidermal trauma to elicit the Koebner response.


Cytokine mRNA profile and cell activation in bronchoalveolar lavage fluid from nonatopic patients with symptomatic asthma.

Recent studies have indicated that airway inflammation in atopic asthma is characterized by T-cell activation and local eosinophilia, but it is unknown whether this also applies to nonatopic asthma. In this study, the cytokine mRNA profile and activation status of inflammatory cells in bronchoalveolar lavage fluid (BALF) of eight nonallergic patients with symptomatic asthma and eight nonallergic healthy controls were compared using the message amplification phenotyping (MAPPing) with the polymerase chain reaction (PCR) procedure and immunocytochemical evaluation. Asthmatics had an increasing number of inflammatory cells in BALF, including activated eosinophils (EG2-positive) (p less than 0.001) and activated T cells (CD25-positive) (p less than 0.001). Activated T cells from five of the eight asthmatic patients and from one control subject expressed high levels of interleukin 5 (IL-5) and granulocyte-macrophage colony-stimulating factor (GM-CSF). All the asthmatic patients had increased numbers of monocytes in their BALF (p less than 0.002) and those cells invariably showed increased expression of interleukin 1 beta (IL1 beta) transcripts. In five patients they also expressed appreciable levels of IL-6 and GM-CSF mRNA. IL-5 and GM-CSF can induce local activation of eosinophils, and IL-1 beta and IL-6 are known to promote T-cell activation and proliferation. Thus, there is an increased production of cytokines with inflammatory properties in the airways of patients with nonatopic symptomatic asthma, which may contribute to the persistence of inflammation, and monocytes and activated T cells are important sources of these cytokines.


Deep venous thrombosis and the risk of pulmonary embolism. A systematic study.

The influence of several diseases and clinical conditions on the presence of pulmonary embolism (PE) in a large series of patients with deep venous thrombosis (DVT) in the lower extremities was analyzed prospectively. Lung scan findings from a series of 434 consecutive patients with DVT (with and without symptoms of PE) were studied and then correlated to five clinical variables: age, sex, elapsed time since clinical symptoms had appeared in the leg to diagnosis, degree of proximity of venous thrombus, and the presence or not of several risk factors that could have predisposed to thrombus development. According to scintigraphic findings, 164 patients were considered to have PE (asymptomatic in 76 of them), while 200 patients were classified as having only DVT. Lung scan was considered to be indeterminate for PE in 70 patients, and they were not included in the study. No differences were found in terms of age, sex, interval of time elapsed since onset of symptoms to diagnosis, or in the degree of proximity of the thrombus. However, several differences between groups were found when comparing the presence or absence of several predisposing factors for thrombosis: DVT developing in immobilized patients was associated with a significantly lower incidence of PE as compared with nonimmobilized patients (p = 0.005). Conversely, patients with a history of venous thromboembolism (VTE) had a significantly higher rate of embolism (31/51 vs 133/313; p = 0.01). On logistic regression analysis, a history of VTE showed a statistically significant association with more than a twofold higher risk of having PE for patients with such an antecedent. Our findings suggest that different pathophysiologic pathways could perhaps explain differences in embolic potential.


Association between neutrophil concentration in bronchoalveolar lavage fluid and recent losses in diffusing capacity in men formerly exposed to asbestos.

It has been observed widely that some individuals exposed to asbestos will experience continued losses of lung function after asbestos exposure ceases. Unfortunately, there are few data on factors that determine clinical course, limiting the clinician's ability to determine prognosis in an individual case and restricting the possibility for testing or targeting any potential intervention to alter the course among the millions at risk. In an attempt to address this question, we studied a volunteer population of 50 such men from among a stable, heterogeneous population of asbestos-exposed workers who had been continuously followed in our occupational medicine clinics for up to 12 years (mean, 6.3 years); most had some clinical or roentgenographic sign of asbestos effect, pleural or parenchymal. Each subject was reexamined clinically, functionally, and roentgenographically. Asbestos and tobacco exposure histories were carefully reviewed with the subjects and quantified based on these reports and available data regarding the various work environments from which they came. Subsequently, each underwent a bronchoalveolar lavage to assess cellularity and levels of various proteins. The levels of risk factors, clinical findings, and biologic parameters from lavage were examined for their relationship to serial changes in lung function during the period over which they had been previously followed. Results of the study demonstrate that serial changes in lung function were not closely related to level or length of prior exposure, smoking behavior, chest roentgenographic findings, or lung volumes. Progressive loss of diffusing capacity for carbon monoxide (Dco) was significantly associated with two factors: level of neutrophil concentration in lavage fluid (0.043 +/- 0.016 ml/min/mm Hg/yr drop for each 0.1 x 10(4) neutrophils per milliliter, p = 0.02) and the level of Dco itself (0.17 +/- 0.07 ml/min/mm Hg/yr drop for each 10 percent decrease in percent Dco predicted, p = 0.01). The relationship with neutrophil concentration was statistically independent of the association with Dco itself and stronger; it persisted when loss of Dco was adjusted for baseline value. Lung volume changes were not associated with any predictor variables, alone or in combination. We conclude that the presence of neutrophils in bronchoalveolar lavage fluid is associated with recent disease progression that may have implications in studies of the mechanisms of asbestos-associated disease and in clinical treatment of patients at risk.


Association between acute inflammatory cells in lavage fluid and bronchial metaplasia.

In epidemiologic studies, airway disease and parenchymal injury are known morbid outcomes of occupational exposure to asbestos. However, the relationship of inflammatory events considered to be responsible for parenchymal injury to the subsequent development of airway injury is unknown. To assess this we performed bronchoalveolar lavage (BAL) and airway biopsies on a population of subjects with exposure to asbestos in the workplace. As an index of airway injury, we employed histologic metaplasia seen in mucosal biopsy specimens. Lung BAL fluid was analyzed for two potentially relevant protein markers and for inflammatory cells recovered from the lower respiratory tract. We related metaplasia to demographic features of this study population (eg, smoking history and asbestos exposure data) and also to the protein and cellular markers recovered by BAL. We studied 50 workers and detected keratinizing metaplasia in 15 and varying lesser abnormalities in the other 28. Cigarette smoking was not associated with the presence of metaplasia (p less than 0.2). Smoking status was associated with an increase in BAL cells (p less than 0.02); however, neither the percent nor concentration of acute inflammatory cells was significantly increased. Acute inflammatory cells (percent and cells per milliliter of BAL fluid) were significantly increased among the subjects with severe metaplasia compared with other study subjects. This increase was true of both neutrophils and eosinophils and the sum of these two (p less than 0.02). Stratification of subjects by smoking status demonstrated a persistent association of inflammatory cells with metaplasia. By logistic regression analysis, polymorphonuclear leukocytes per milliliter and eosinophils per milliliter were significantly related to the presence of metaplasia in two independent models (odds ratios, 9.9 and 7.6, respectively). Cigarette smoking and other demographic or BAL variables were not significantly associated with metaplasia in these models.


Comparison of six oxygen delivery systems for COPD patients at rest and during exercise.

Five different oxygen-conserving devices were tested in each of ten oxygen-dependent patients with COPD who had met the NOTT criteria for continuous oxygen use. They were tested on room air, their prescribed continuous oxygen flow and then on each of the five devices. The devices which delivered a bolus of oxygen during early inspiration or increased oxygen delivery as the respiratory rate increased did better than those devices which delivered oxygen at a normal flow rate during inspiration or a fixed portion of inspiration. In at least one of the subjects each device was associated with desaturation to less than 80 percent during a 12-min walk. It is concluded that oxygen-conserving devices vary in their ability to maintain SaO2 levels during exercise. It is recommended that a home oxygen evaluation include measurement of an exercise SaO2 utilizing the prescribed oxygen delivery system.


Comparison of three different methods used to achieve local anesthesia for fiberoptic bronchoscopy.

A patient's tolerance of fiberoptic bronchoscopy depends on the effectiveness of local anesthesia. This study compares the three different methods of local anesthesia in common use After sedation, patients (n = 53) received either 4 ml of 2.5 percent cocaine by intratracheal injection (TI) (n = 18), by bronchoscopic injection (BI) (n = 19), or had 4 ml of 4 percent lidocaine delivered by nebulizer 20 min before the procedure (NEB) (n = 16). Patients and bronchoscopists scored the procedure using visual analog (VAS) and severity scales. Objective measurements of cough counts and episodes of stridor were recorded by phonopneumography. Patients' VAS scores showed a clear preference for the transtracheal method compared with either bronchoscopically injected cocaine (p less than 0.001) or nebulized lidocaine (p less than 0.001). Patients also reported that the TI method produced less cough during intubation of the larynx and inspection of the airways (BI and NEB, p less than 0.01). The TI method was also preferred by the bronchoscopists (BI and NEB, p less than 0.001); they reported less cough and easier tracheal intubation. The mean cough count was significantly lower for the TI group, 49 (43) compared with 95 (52) for BI (p less than 0.01), and 81 (43) for the NEB group (p less than 0.05). Patients' and bronchoscopists' VAS showed significant correlation with cough (r = 0.63-69, p less than 0.01). Stridor occurred in only two patients after TI, compared with 15 in the other two groups. Extra local anesthesia was required by 16 patients after BI, by all the NEB group, but by only one patient after TI. Subjective and objective measurement shows that 4 ml of 2.5 percent cocaine injected into the trachea produced excellent local anesthesia for fiberoptic bronchoscopy, there were no extra complications, and it was the method preferred by both patients and bronchoscopists.


Short- and long-term hemodynamic effects of oral nifedipine in patients with pulmonary hypertension secondary to COPD and lung fibrosis. Deleterious effects in patients with restrictive disease.

The present study was undertaken to evaluate at rest the short- and long-term effects of oral nifedipine (N) in patients with pulmonary hypertension (PH). A prospective study with ten consecutive cases during two years in a setting of a district acute hospital. Seven patients with advanced COPD and three with severe lung fibrosis (LF) during a period of stable condition. Three patients with COPD were eligible for the long-term investigation. Right heart catheterization with a 7F Swan-Ganz triple-lumen thermodilution catheter and radial cannulation with a 3F arterial catheter. Measurement of CO, MAP, RAP, PAP, PWP, HR, and ABG and calculation of CI, TSR, PAR, and DO2 before and after 20 mg of N sublingually at rest. For the group as a whole, N induced a reduction in MAP and TSR, with a significant increase in CI and DO2. There were no significant changes in PAP, PAR (magnitude of the reduction: -10 percent), HR, and PaO2. The individual analysis of the driving pressures (PAP-PWP) in function of the cardiac output demonstrated that a real vasodilating effect in the pulmonary circulation occurred in only three COPD patients (magnitude of the PAR reduction: -43 percent), while in the three patients with LF, N induced a deleterious increase in PAP and PAR. After long-term treatment (10 mg of N daily every 4 h; average 12 months) in the former, despite a persistent beneficial hemodynamic effect (magnitude of the PAR reduction: -36 percent), there was the usually expected clinical worsening. N in small doses may be able in some patients with severe COPD to induce a beneficial short- and long-term hemodynamic effect on the pulmonary circulation when PH is present. On the other hand, N should not be used in patients with PH and advanced LF.


Bronchiolitis obliterans organizing pneumonia. Clinical features and differential diagnosis.

The clinical features of 34 Japanese patients with bronchiolitis obliterans organizing pneumonia (BOOP) are discussed. Thirty-two patients (94 percent) had symptoms of cough, fever, or dyspnea. On chest roentgenograms, bilateral patchy infiltrates were seen most frequently in 23 patients (68 percent), followed by small linear opacities in five (15 percent), both patchy infiltrates and reticulonodular opacities in four (12 percent), and reticulonodular opacities in two (6 percent). The bronchoalveolar lavage fluid (BALF) cell findings obtained from 26 patients revealed an increase in the percentage of lymphocytes in 20 patients (77 percent), neutrophils in 15 (58 percent), and eosinophils in 16 (62 percent), and a decrease in the CD4+/CD8+ ratio in 14 of 23 patients (61 percent). Corticosteroids were administered to 25 patients. Except for one patient who died, the prognosis was good in all patients. Further, in patients without corticosteroid therapy, the prognosis was good.


Effects of stopping long-term vasodilator therapy in patients with chronic aortic insufficiency.

We studied the effects of stopping long-term vasodilator therapy in 17 patients with chronic stable aortic insufficiency. These patients received hydralazine for 37 +/- 15 months (mean +/- SD) and, as a result, had experienced a significant decrease in left ventricular volumes. All patients were followed clinically and ten of the patients underwent serial radionuclide evaluation at baseline, while receiving drug, and at 20 +/- 7 months after stopping drug therapy. No patient showed evidence of acute clinical deterioration when drug therapy was stopped. The rate of progression to valve replacement due to onset of symptoms or left ventricular dysfunction was not significantly different from that previously reported in a population with similar characteristics. Left ventricular size, however, returned to levels similar to baseline after drug therapy was stopped. We conclude that long-term vasodilator therapy may be discontinued in patients with chronic stable aortic insufficiency without causing clinical deterioration or significant alteration in rate of progression to valve replacement.


Intermittent administration of furosemide vs continuous infusion preceded by a loading dose for congestive heart failure.

Several reports have suggested that continuous intravenous administration of loop diuretics may be superior to intermittent administration. We performed a prospective randomized crossover study comparing intermittent intravenous administration (IA) of furosemide with continuous infusion following a single loading dose (LDCI) in nine patients with severe congestive heart failure. At the time of hospital admission, patients were randomly assigned to one of two treatment groups. One group (four patients) received an IV bolus injection of furosemide followed immediately by a continuous infusion for 48 h. The second group (five patients) was treated with three IV bolus injections a day for 48 h. Total doses of furosemide were equivalent in the two groups. After 48 h, each patient was crossed over to the other method and treated for an additional 48 h. LDCI produced significantly greater diuresis and natriuresis than IA (total urine output increased by 12 to 26 percent, total sodium excretion increased by 11 to 33 percent) (p less than 0.01). There were no significant differences in side effects between the two methods. These results indicate that LDCI may be a preferred method for administration of furosemide in patients with congestive heart failure.


Bronchodilator testing "confidence intervals" based on the level of bronchial responsiveness.

"Confidence intervals" based upon inhalation of placebo have been proposed as criteria for defining a significant response to an inhaled bronchodilator. The published intervals were derived from a clinically heterogeneous population. We calculated the difference (delta) between spirometric data before and after placebo in 109 consecutive patients referred for methacholine bronchoprovocation challenge testing. The mean delta, expressed both as a percent change and as actual volume change for both the FVC and FEV1, was not significantly different in patients with bronchial hyperresponsiveness, as compared to subjects with a negative methacholine challenge test; however, the variance of measurements in hyperresponsive subjects was significantly greater than that of the normal population. In addition, as the category of responsiveness increased from mild to moderate to severe hyperresponsiveness, so did the variance within these groups. A negative correlation between the measured PC20FEV1 and the volume and percent change was noted. We conclude that patients with hyperresponsive airways may display increased spirometric variation before and after placebo. This general approach for establishing normal limits for defining a significant response appears to be valid, but the actual values used may vary, depending on the composition of the population tested and the goals of the study. Also, the use of the term, "confidence intervals," in this context is inappropriate; and we propose, instead, the use of percentiles and the simpler terms, upper 90th or 95th percentiles.


Transbronchial lung biopsy. Histopathologic and morphometric assessment of diagnostic utility.

The diagnostic utility of transbronchial lung biopsy (TBB) is partly a function of its size. However, objective parameters that reflect biopsy specimen size have not yet been well-defined. We studied clinical records and histopathologic lung tissue slides of 116 patients who underwent diagnostic TBB, aiming to define the possible significance of association between seven parameters and three categories of pathologic diagnoses. Three of the seven parameters were clinical: age, sex, and chest roentgenographic infiltrates (localized vs diffuse). The remaining four parameters were histopathologic and morphometric: total number of tissue fragments, total number of alveoli (per biopsy specimen), total tissue area (alveolated plus nonalveolated), and lung total area (alveolated tissue alone). The three categories of pathologic diagnoses were as follows: infection, tumor, and nonspecific diagnoses. The nonspecific diagnoses included diagnoses of fibrosis and/or chronic inflammation. The alveoli were microscopically counted by one of us (S.D.G.). The number of biopsy fragments, the total tissue area, and the total lung area were measured in square millimeters by a computer-assisted digitizing system using specific (Bio-Quant) software (R and M Biometrics Inc). The significance of the associations between the seven parameters and the three diagnostic categories were assessed by the chi2 test for association. Overall, the following four possible associations were found to be statistically significant: (1) age--a lower percentage of patients with infection was found among patients with increasing age (p less than 0.001); (2) roentgenographic findings--a greater percentage of tumor diagnoses were found in patients with localized infiltrates (p = 0.006); (3) number of biopsy fragments--a greater percentage of patients with diagnoses of infection was identified among patients whose biopsy specimens contained the highest number of tissue fragments (p = 0.04); and (4) number of alveoli--a greater percentage of diagnosis of infection was made in patients whose biopsy specimens contained greater than or equal to 20 alveoli (p = 0.01). Our findings support the notion that the diagnostic utility of TBB is related to its size. However, this relationship between TBB size and diagnostic utility was apparent only for diagnoses of infection and not for diagnoses of tumor. We conclude that TBB specimens containing 20 or more alveoli may (1) be declared to be adequate for diagnosis, (2) in the appropriate clinical setting, they will be most likely to yield a diagnosis of infection, and (3) the number of alveoli does not appear to be associated to the diagnosis of tumor.


Distilled water challenges in asthmatic children. Comparison of different protocols.

Inhalation of ultrasonically nebulized distilled water (UNDW) appears a promising candidate for routine challenge testing in bronchial asthma. We have compared two different methods of application of UNDW in 12 asthmatic children with a positive response to methacholine provocation (MCh), in an attempt to increase UNDW sensitivity and to establish standard testing protocols. In addition, results from UNDW challenges were compared to responses to inhalation of jet-nebulized distilled water (JNDW) and cold air (CACh). Compared to MCh, the sensitivity of continuously or intermittently (iUNDW) inhaled UNDW was 67 percent or 75 percent, respectively, when a positive response was defined by a greater than or equal to 20 percent fall in FEV1, but was higher when definition of a positive response was based on results from flow volume curves. Sensitivity of continuous or intermittent inhalation of JNDW was lower than for UNDW. The UNDW inhalations were better tolerated than CACh. Following stepwise iUNDW challenge, there was a clear reaction plateau for all variables measured. Results indicate that testing protocols with iUNDW inhalations over 6 to 10 min (corresponding to 7 to 11 ml water inhalation) yield the maximum sensitivity attainable with UNDW challenges, and require a minimum of patient and investigator effort.


Histamine challenge in young children using computerized lung sounds analysis.

The use of the histamine challenge test (HCT) for the diagnosis of asthma has so far been limited to older children who can perform spirometry consistently. Recently, wheeze detection by tracheal auscultation with analog recording into a tape recorder has been utilized in young children in place of spirometry. Wheezing can also be identified using computerized lung sounds analysis (LSA) by a typical pattern on spectral analysis. Our aim was to develop a practical computerized system in which the response to histamine could be identified in an objective manner and documented on hard copy. Lung sounds were recorded with a Hewlett-Packard HP 21050A contact sensor placed over the right upper anterior chest. Sounds were amplified, band-filtered (50 to 2,000 Hz), and digitized at a sampling rate of 5.5 kHz into a Macintosh SE computer, and spectral LSA was performed. To validate our method, six older children (ages 9 to 16 years) with mild or moderate asthma underwent HCT. The identification of typical wheezing pattern (discrete, high-amplitude power peaks) on LSA was compared to 20 percent fall in FEV1 (PC20) and symptoms (cough, wheeze, chest tightness). In five children, the histamine concentration required to produce the characteristic wheezing pattern on LSA was half that required to produce a 20 percent fall in FEV1. In the sixth patient, wheezing on LSA and PC20 occurred at the same histamine concentration. To determine the technique's applicability to young children, we then studied six young asthmatic children (age 2 to 5 years). All children showed the wheezing pattern at a histamine concentration of 25 percent or 50 percent (one or two steps prior) to that producing symptoms (cough, wheeze, chest tightness) or wheezing on tracheal auscultation. Six age- and sex-matched nonasthmatic children (control subjects) did not show this pattern on LSA and had no symptoms or tracheal wheeze with HCT. We describe a sensitive method enabling application of HCT to young children who are unable to perform spirometry. This method is as sensitive as, and often more sensitive than, conventional PC20 with spirometry or tracheal auscultation.


Determinants of airway response to challenge with distilled water in a population sample of children aged 7 to 10 years old.

We challenged 446 schoolchildren and measured the percent decrease in FEV1 following 10 min of tidal inhalation of UNDW. Assessment tools for respiratory symptoms and atopy were questionnaire and skin testing, respectively. A previous diagnosis of asthma was most strongly associated with a positive airway response (defined as a fall in FEV1 greater than or equal to 10 percent. A positive response was also associated with atopy, presence of cough, cough during night, or any respiratory symptom. A child's age and the prechallenge FEF75% also explained response to distilled water indicating less responsiveness for older children and those with relative greater airway diameter. For the previous diagnosis of asthma, a positive distilled water challenge test had a sensitivity of 36 percent and a specificity of 92 percent. We conclude that a significant relationship between airway response to distilled water, asthma and symptoms suggestive for asthma exists for a childhood population sample.


The amplitude of circadian FEV1 variation suitable for phase determination by cosinor analysis in stable asthmatic children.

To elucidate the criterion for amplitude of circadian FEV1 variation suitable for phase analysis, six FEV1 measurements within a day were made on 346 days in 125 stable asthmatic children aged 8 to 12 years. Since coefficient of variation (CV) of FEV1 within a day in nonasthmatic children in our laboratory is less than 5 percent, circadian FEV1 variations were divided into CV greater than or equal to 5 percent and CV less than 5 percent groups. Forty-two (12 percent) variations with significant fit of cosinor rhythm were CV greater than or equal to 5 percent. Troughs in 32 (76 percent) variations of the 42 were distributed between 12 PM and 6 AM, and the deviation was highly significant against a uniform distribution (p less than 0.001). This was consistent with nocturnal asthma. Thirty-five (10 percent) variations with significant fit of cosinor rhythm were CV less than 5 percent. Troughs in 12 (34 percent) variations of the 35 were distributed between 12 PM and 6 AM, and the deviation from a uniform distribution was nonsignificant. These suggest that 5 percent or more of CV of FEV1 may be clinically suitable for analysis of circadian FEV1 variation.


Repeated methacholine challenge produces tolerance in normal but not in asthmatic subjects.

Repeated methacholine challenge in normal nonasthmatic subjects (who require higher doses of methacholine than do asthmatic subjects to produce a 20 percent decrease in FEV1) can produce progressively diminishing methacholine responsiveness (or tolerance) with serial challenges. To determine whether tolerance to methacholine occurs in asthmatic subjects as it does in nonasthmatic subjects, we studied eight young (mean age, 24 years) mild asthmatic patients (occasional but not regular use of bronchodilator medications, PC20 methacholine range 0.1 to 7.0 mg/ml) who underwent five sequential methacholine challenges at 1.5-h intervals. Serially increasing concentrations of methacholine were given until FEV1 fell by 20 percent. Results were compared with those in seven nonasthmatic control subjects who underwent an identical protocol. As seen in previous studies, the normal subjects demonstrated significant tolerance to methacholine when each of five challenges was compared to the first. By contrast, in the asthmatic group, the mean cumulative dose of methacholine producing a 20 percent fall in FEV1 in the fifth challenge was not significantly different from the dose required in the first challenge. These results indicate that marked tolerance to methacholine does not occur in mild asthmatic patients with multiple repeated challenges over 6 h. The lower cumulative dose of methacholine required by asthmatic patients may be insufficient to produce tolerance.


Currarino-Silverman syndrome (pectus carinatum type 2 deformity) and mitral valve disease.

Currarino-Silverman syndrome is a rare disorder characterized by premature fusion of manubrio-sternal joint and the sternal segments, resulting in a high carinate chest deformity; it is frequently associated with congenital heart disease. Among the various heart lesions reported in this syndrome, mitral valve disease and coarctation of the aorta have not yet been described (to our knowledge). Our report consists of five children with this syndrome, four of whom had mitral valve disease, with an associated coarctation of the aorta in one patient. The fifth patient had an innocent heart murmur.


Idiopathic hypertrophic cardiomyopathy in identical twins. Morphological heterogeneity of the left ventricle.

We report a pair of identical twins with HC with varying extent of left ventricular hypertrophy and some degree of left ventricular outflow tract obstruction. The diagnosis of identical twins was based on the same sex, blood typings, HLA typings and hybridization patterns to four hypervariable DNA probes. Identical twins are derived from a single zygote and are genetically homogeneous human beings. The present report suggests that heterogeneity in the morphologic expression of HC may not be solely attributed to genetic factors. Environmental factors also may play an important role.


Enhancement of theophylline clearance by oral albuterol.

The possible effect of albuterol on theophylline clearance was studied in ten adult volunteers. Subjects received intravenous aminophylline loading dose (5.6 mg/kg), with oral albuterol (4 mg every 6 h), or inhaled albuterol (200 micrograms every 6 h), or alone (control). Theophylline levels were determined for 12-h periods. Theophylline clearance and elimination t 1/2 were calculated. Theophylline clearance was significantly higher when given with oral albuterol, in comparison with control (0.83 +/- 0.05 vs 0.73 +/- 0.06 ml/kg/min, p less than 0.02). Theophylline elimination t 1/2 was shorter with the coadministration of oral albuterol, compared with control (7.1 +/- 0.3 vs. 8.1 +/- 0.6 h, p less than 0.02). These alterations in theophylline clearance and elimination were greater in subjects who had lower control theophylline clearance. Theophylline clearance and elimination t 1/2 recorded with inhaled albuterol were not significantly different from control values. Coadministration of oral albuterol and theophylline resulted in enhancement of theophylline clearance, particularly in subjects with initially slow theophylline elimination. Such patients may require theophylline dosage adjustment as a result of this interaction.


Multidrug resistant Mycobacterium tuberculosis in patients with human immunodeficiency virus infection.

Multidrug resistant Mycobacterium tuberculosis (MDR-MTB) infection has not been recognized as a serious problem in patients with human immunodeficiency virus (HIV) infection. Multidrug resistance (MDR) has appeared in our medical center in 24 out of 72 patients between January 1990 and May 1991 compared to 8 out of 132 patients within the period from 1982 to 1987 (relative risk 5.50 with 95 percent confidence interval 2.61 to 11.61). We describe 19 patients with MDR in MTB (isoniazid and at least one additional first line drug), who had serologic evidence of HIV infection, 13 of whom were diagnosed with acquired immunodeficiency syndrome (AIDS). The MTB cultures from 10 out of 19 patients with MDR were resistant to three or more drugs. Fifteen patients died although 9 out of these 15 had received at least a four-drug regimen for a mean time of seven weeks (range 2 to 12). This increase in MDR was seen in ten homosexuals and nine intravenous drug users. This rapid appearance of MDR-MTB strains is worrisome. New strategies for empiric therapy of such patients while awaiting sensitivity data are needed.


Homeless individuals and drug-resistant tuberculosis in south Texas.

Drug-resistant tuberculosis was found in 21 percent of homeless individuals in New York City between 1982 and 1987. To see if this relationship existed in south Texas, we evaluated all admissions to a Texas Health Department facility with culture-proven tuberculosis. Four hundred forty-three patients were admitted between September 1987 and October 1990. Twenty-six, (5.9 percent) of these patients were identified as homeless. Alcoholism, tobacco abuse, divorce, and unemployment were common demographic characteristics. Six male patients and one female patient (27 percent) had Mycobacterium tuberculosis resistant to one or more antituberculosis drugs. Five were Hispanic, one was white, and one was black. The six male patients had resistance to only one drug, either rifampin or ethambutol. The female patient had resistance to streptomycin, isoniazid, and rifampin. These findings illustrate that drug-resistant tuberculosis exists among homeless individuals in south Texas. As the number of homeless people increases, physicians need to recognize that pulmonary tuberculosis is a frequent infection in this population and that the causal mycobacteria may well be resistant to one or more antituberculosis agents.


Measurement of lung density by means of quantitative CT scanning. A study of correlations with pulmonary function tests.

In recent years, much attention has been given to the role of CT in detecting and quantitating pulmonary emphysema. We measured CT lung density in 45 patients undergoing a diagnostic work-up and compared this with pulmonary function tests. The CT lung densities measured with the sector method and with the whole lung method were very highly correlated with each other (r = 0.96, p less than 0.001), and measurements at TLC systematically gave a lower density than those at FRC (p less than 0.001). Also, CT density measurements at TLC and even more so at FRC correlated well with pulmonary function indices of airway obstruction and of hyperinflation, but not with indices that are considered more specific for emphysema (single breath DCO, static lung compliance) We conclude that CT lung-density gives a good reflection of the degree of hyperinflation, ie, enlargement of distal airways, but is not sensitive to detect whether or not this is associated with emphysema.


Migration of neutrophils from the lung into the pleural space after lung resection in humans and rabbits.

The origin of neutrophils that are found in pleural effusions after pulmonary resection is unknown. We measured neutrophil counts in pleural effusion sequentially for 48 h in patients who had undergone partial resection or pneumonectomy. Additionally, we measured neutrophil counts in the pleural effusions separately from the visceral pleura and parietal pleura in rabbits. In humans, we found that the maximum neutrophil counts in pleural effusion occurred more often in the patients who underwent partial resection (11.7 +/- 6.0 x 10(4) cells/microL) than in the patients who underwent pneumonectomy (3.7 +/- 1.2 x 10(4) cells/microL). There was no difference between neutrophil counts in blood of pneumonectomy group and that of the partial resection group. In rabbits, neutrophil counts were 1.5 times greater in the pleural effusion derived from the lung than in that derived from the parietal pleura. We conclude that movement of neutrophils occurs primarily from the lung into the pleural space after lung resection in humans and rabbits.


Effects of inhaled platelet activating factor on bronchial responsiveness in patients with symptomatic and asymptomatic pulmonary embolism.

To determine the possible role of platelet-activating factor (PAF) in pulmonary embolism (PE), the reactivity of the airways to inhaled PAF, using doses ranging from 6.25 to 400 micrograms, was examined in 24 patients with a past episode of PE. Twelve of these patients had experienced acute respiratory insufficiency during the episode (with or without additional symptoms). None of the remaining 12 patients had experienced any respiratory symptoms during the PE episode. Diagnosis was established by means of a ventilation-perfusion lung scan performed when admitted to the hospital because of deep venous thrombosis (DVT) in the lower limbs. Nonspecific bronchial reactivity as measured by the response to bronchoprovocation testing with methacholine showed no significant differences between both groups. PAF caused a dose-dependent bronchoconstriction defined by at least a 35 percent decrease in specific airway conductance (SGaw) in all patients. The average dose of PAF needed to decrease SGaw 35 percent was significantly lower in patients who had had a symptomatic PE than in those with asymptomatic PE (p = 0.011). This finding suggests that patients who suffered from symptomatic PE may present a greater airway reactivity to inhaled PAF. This different behavior might explain the existence of some of the respiratory symptoms of PE, which could be attributed to PAF-related effects. However, additional studies are needed to evaluate the role of PAF in PE.


Breathlessness in patients with severe chronic airflow limitation. Physiologic correlations.

We wished to identify the physiologic abnormalities that distinguish severely breathless (SB) patients with chronic airflow limitation (CAL) from mildly breathless (MB) patients. Thirty-seven patients with stable, advanced CAL (FEV1 = 38 +/- 10 percent predicted, mean +/- SD) were separated into two distinct groups, SB and MB, solely on the basis of their baseline dyspnea index (BDI). BDI ratings in SB (n = 17) and MB (n = 20) patients were 2.5 +/- 1.5 and 8.5 +/- 1.5 (mean +/- SD), respectively (p less than 0.001). Groups were compared with respect to pulmonary function, breathing pattern parameters, arterial blood gases (ABGs), and responses to progressive exercise. Steady-state gas-exchange parameters were measured in a subgroup of 16 patients during exercise. There were no significant intergroup differences in dynamic flows, plethysmographic lung volumes, ABGs, resting ventilation, or breathing pattern parameters. However, the SB group had significantly lower single-breath diffusing capacities for carbon monoxide (Dco) (by an average of 50 percent, p less than 0.001), together with significantly higher resting ventilatory equivalents for carbon dioxide (VE/VCO2) (by 17 percent, p less than 0.01) and dead space to tidal volume ratios (by 11 percent, p less than 0.05). Ventilatory responses for a given metabolic load were, on average, 33 percent higher (p less than 0.05) in the SB group reflecting greater ventilation-perfusion inhomogeneity and wasted ventilation. The SB subgroup (n = 7), in contrast to the MB subgroup (n = 9), demonstrated significantly (p less than 0.01) greater O2 desaturation during exercise; PaO2 decreased in SB and MB at peak exercise by -13 +/- 7 mm Hg and -4 +/- 2 mm Hg (mean +/- SD), respectively. Stepwise regression analysis selected DCO and VE/VCO2 as the only predictors of breathlessness in this group, accounting for 52 percent of the variance in BDI (F-ratio = 18.49, p less than 0.001). Although the origin of breathlessness is multifactorial, variation in its intensity among patients with comparable levels of airflow limitation can be accounted for, in part, by underlying pathophysiologic differences. Severely breathless patients were characterized by lower resting diffusing capacities and accelerated ventilatory responses to exercise.


Proliferative characteristics of fibroblast lines derived from open lung biopsy specimens of patients with IPF (UIP).

We compared the doubling time of fibroblasts derived from idiopathic pulmonary fibrosis (usual interstitial pneumonia) (IPF [UIP]) lung tissues and control fibroblasts, cultured in usual growth medium, and examined the response of these fibroblasts to platelet-derived growth factor (PDGF) and prostaglandin E2 (PGE2). Ten fibroblast lines from open lung biopsy specimens of patients with IPF (UIP) and ten control fibroblast lines from surgically resected lung tissue of patients with limited lung diseases were established. The average doubling time of fibroblast lines was 32.0 +/- 6.0 h (mean +/- SD) in UIP and 33.2 +/- 10.4 h in controls, showing no difference between the two groups. To examine the responses of fibroblasts to PDGF and PGE2 and the differences between fibroblasts derived from fibrotic tissues with different intensity of fibrosis, lung specimens from five patients with IPF were subdivided into two groups, higher-intensity fibrotic lesions (H) and lower-intensity fibrotic lesions (L). The fibroblast lines were established separately. 3H-thymidine uptake with or without PDGF or PGE2 was examined. Results were expressed as the index of thymidine incorporation into the fibroblasts. There were no differences in the doubling times and the responses to PDGF and PGE2 between H and L. There were no differences between control and H regarding their response to PDGF. In response to PGE2, the growth inhibition for H was significantly decreased compared with the control (p less than 0.05). There was no difference in growth inhibition between H and L. The finding that PGE2 inhibits fibroblast proliferation less in UIP lung tissue suggests that fibroblasts from UIP were functionally altered cells or, to some extent, out of normal regulation. These results suggest an abnormal proliferation of fibroblasts observed in IPF (UIP).


Abnormal oxygen uptake responses to exercise in patients with mild pulmonary sarcoidosis.

Exercise intolerance and exertional dyspnea are common complaints in patients with sarcoidosis. Although in many cases these complaints are attributable to restrictive or obstructive lung mechanics or inefficiency of pulmonary gas exchange, other processes also may contribute to impairment in exercise function and may not be readily detected or distinguished from problems of lung mechanics on the basis of symptoms or routine laboratory testing. To identify the frequency and etiology of impaired exercise capacity in sarcoidosis patients with mild lung disease, integrative cardiopulmonary exercise testing was performed in 23 patients. Breath-by-breath measurements were made of gas exchange, ventilation, and heart rate. In 9 of 20 evaluable patients, the oxygen uptake (VO2) at the anaerobic threshold was low, and/or the rate of increase of VO2 was abnormal relative to work rate or heart rate, suggesting a defect in cardiocirculatory function. Resting and exercise echocardiography revealed normal left ventricular ejection fractions and wall motion in all nine of these patients, but findings suggestive of right ventricular hypertrophy and/or right ventricular dysfunction were present in five. Abnormal responses of VO2 during exercise are common in patients with sarcoidosis and may be due to subclinical impairment of right-sided cardiac function.


Nocturnal nasal IPPV stabilizes patients with cystic fibrosis and hypercapnic respiratory failure.

Nocturnal nasal intermittent positive pressure ventilation (nIPPV) has been used successfully in the management of patients with respiratory failure due to chest wall deformity and neuromuscular disease. In order to determine if nIPPV is useful in patients with cystic fibrosis (CF) complicated by respiratory failure, we treated four hypercapnic patients for up to 18 months. All patients had failed to respond to intensive conventional therapy, including nocturnal nasal CPAP in three of the patients. Within a few days of commencing nIPPV, all reported improved length and quality of sleep. There was lessening of the degree of hypercapnia and an increase in respiratory muscle strength. After stabilization in the hospital, all patients were able to be discharged home receiving nocturnal assisted ventilation. The improvements seen in these patients have been maintained for up to 18 months. We believe nIPPV offers an effective therapeutic approach for patients with end-stage CF in hypercapnic respiratory failure and may be particularly advantageous for those awaiting heart-lung transplant.


Pulmonary dirofilariasis. The largest single-hospital experience.

Pulmonary dirofilariasis caused by Dirofilaria immitis, the dog heartworm, is a rarely reported pulmonary lesion. It most often appears as a solitary pulmonary nodule, often mistaken for a primary or metastatic lung tumor, and the diagnosis is not often established until thoracotomy with excisional lung biopsy is performed. Sporadic reports of pulmonary dirofilariasis in the United States total only 87 cases. The ten resections of pulmonary dirofilariasis at the Methodist Hospital in Houston, Tex, represent the largest reported series of cases originating at a single hospital. We present an overview of the pathogenesis of this disease, its clinical manifestations and epidemiologic features. The prevalence of pulmonary dirofilariasis appears to be increasing. Thus, surgeons and pathologists need to be aware of this etiology of granulomatous pulmonary lesions.


Indomethacin and methacholine tolerance in normal subjects. Role of prostaglandin synthesis in the attenuation of methacholine's effect during repeated inhalation challenges.

Within hours, tolerance occurs to repeated methacholine challenge in normal subjects, and this study examines whether prostaglandin synthesis produces this phenomenon. On two separate study days, ten nonasthmatic non-smoking subjects with measurable baseline responsiveness to methacholine performed five sequential methacholine challenge tests over 6 h. Pretreatment before each day consisted of either placebo tablets or 50-mg tablets of indomethacin given three times daily for 48 h prior to testing. Medications were administered in a single-blind crossover fashion, with study days assigned in random order and separated by at least 1 wk. Methacholine challenge tests were summarized by the PD20FEV1 (the provocative dose in cumulative breath units [cbu] required to produce a 20 percent fall in FEV1). Indomethacin pretreatment had no effect on baseline spirometry between the two study days; however, the baseline geometric mean PD20FEV1 fell from 145 +/- 2 cbu (+/- percent SD) after placebo pretreatment to 65 +/- 1 cbu (+/- percent SD) on the indomethacin day (p = 0.046). This effect of indomethacin on baseline airway responsiveness persisted when an additional ten subjects were studied to further investigate this finding. Significant tolerance to repeated methacholine challenges occurred on both study days, with geometric mean PD20FEV1 rising approximately 16-fold (p less than 0.0001) regardless of pretreatment received. This study demonstrates that the attenuation of methacholine's effect with repeated testing is not due solely to prostaglandin synthesis and must involve, in part, other mechanisms, such as changes in methacholine deposition, agonist-receptor interactions, or postreceptor responses. In addition, prostaglandin inhibitors may increase baseline methacholine responsiveness in healthy nonasthmatic subjects.


Small airways dysfunction in systemic sclerosis. A controlled study.

A debate exists regarding the importance of small airways disease in systemic sclerosis, while smoking seems to have a major effect on the exact prevalence. In order to evaluate small airways dysfunction (SAD) in a pure systemic sclerosis population, we performed pulmonary function studies in 31 nonsmoking patients and 31 age- and sex-matched nonsmoking control subjects. Patients' FVC, TLC, and Dco mean values were significantly lower compared with the corresponding values of the controls (p less than 0.05), while there was no difference in MEF25, RV, and RV/TLC. Seven (22.6 percent) of 31 patients and four controls (a nonsignificant difference) had evidence of SAD, namely a maximum expiratory flow at 25 percent of vital capacity (MEF25) less than 60 percent of predicted. Positive correlation (p less than 0.001) was found between MEF25 and FEV1/FVC in the patients. Moreover, no differences were found in abnormal lung function patients with and those without SAD in demographic, clinical, roentgenologic, and serologic features and results of pulmonary function tests. These findings suggest that SAD in our patients is not a characteristic and early manifestation of systemic sclerosis and that, when present, it is not correlated with the severity of the pulmonary involvement in scleroderma.


Impairment of lung mucociliary clearance in pigeon fanciers.

Lung mucociliary clearance was measured in 15 pigeon fanciers. The study group was subdivided into two: a precipitin-positive group (n = 10; mean +/- SEM age 45 +/- 5 years) with circulating blood precipitins and a precipitin-negative group (n = 5; mean +/- SEM age 40 +/- 3 years) without. Clearance was measured using an objective, noninvasive radioaerosol technique. The data for both groups were compared with those of matched control groups of healthy subjects. The mean +/- SEM area under the tracheobronchial retention curves (AUC) over the 6-h observation period was 257 +/- 27 %h for the precipitin-positive group compared with 177 +/- 16 %h for its control group (p = 0.02)--a high AUC value denoting slow clearance. That for the precipitin-negative group was 282 +/- 34 %h compared with 150 +/- 15 %h for its control group (p = 0.02). Our study illustrates in pigeon fanciers involvement of the conducting airways in that a major defense mechanism of the airways--namely, mucociliary clearance--is substantially compromised. The presence or absence of precipitins appears not to be related to the degree of mucociliary clearance impairment.


Corticosteroids for Pneumocystis carinii pneumonia with acute respiratory failure. Experience with rescue therapy.

Corticosteroids have proven effective as adjunctive therapy for the treatment of PCP in patients with AIDS, when begun within 72 h of conventional anti-Pneumocystis therapy. Their efficacy as rescue (or salvage) therapy in patients who have failed conventional therapy, however, remains unproven. Ths report presents our experience with 16 patients admitted to our MICU for acute respiratory failure (PaO2/FIO2 ratio less than or equal to 150) due to PCP. Five of six patients (83 percent) who received "primary" CS rescue (initial CS use prompted by acute respiratory failure after 72 h of conventional anti-Pneumocystis therapy) survived hospitalization. Our experience suggests that CSs may be effective even when started after 72 h of conventional therapy. Additional studies are needed to clarify the role of CS rescue therapy.


A comparison of three pulmonary artery oximetry catheters in intensive care unit patients.

To compare the clinical performance of three pulmonary artery oximetry catheters (Oximetrix 3, SAT-2, and HEMOPRO2) in intensive care unit (ICU) patients. Unblinded comparison of performance over 24 h using an IL-282 CO-oximeter as a criterion standard. Multispecialty adult ICU at a university teaching hospital. Thirty critically ill patients selected from those requiring hemodynamic monitoring for medical management. By all measures, performance of the Oximetrix 3 and SAT-2 systems were comparable; bias +/- precision were -1.98 +/- 3.07 and +1.80 +/- 3.49, respectively, vs -2.28 +/- 5.24 for the HEMOPRO2. The Oximetrix 3 and SAT-2 systems demonstrated consistent performance over the range of saturations tested, though Oximetrix 3 tended to underestimate and SAT-2 tended to overestimate the CO-oximeter value. The HEMOPRO2 underestimated the CO-oximetry-derived saturation, although this was not constant across the range of values tested. The 95 percent confidence limits based on intrasubject variability were similar (+/- 4.59, +/- 5.66, and +/- 6.56 for the Oximetrix 3, SAT-2, and HEMOPRO2, respectively); however, the 95 percent confidence limits based on total variability, while similar for Oximetrix 3 (+/- 6.03) and SAT-2 (+/- 6.86), were larger for the HEMOPRO2 (+/- 10.30). The expected SD was similar for the three systems (2.03, 2.50, and 2.90 for the Oximetrix 3, SAT-2, and HEMOPRO2 systems, respectively). None of the systems equaled or exceeded (p greater than 0.05) the manufacturers' published specifications, which, in all cases, are listed as +/- 2 percent (saturation; 1 SD) when compared with bench oximetry. Although each system measures mixed venous oxygen saturation, the Oximetrix 3 and SAT-2 systems demonstrate closer agreement with CO-oximetry. However, none of these catheters provided statistically significant evidence that they would perform within +/- 2 percent of CO-oximetry. As a continuous monitor used to detect changes or trends, any of the three may be acceptable.


Relationship of oxygen consumption and oxygen delivery in surgical patients with ARDS.

Previous studies have described oxygen delivery (DO2) and oxygen consumption (VO2) relationships in patients with ARDS and other acute diseases that suggest occasions when VO2 may be dependent on the supply of oxygen, ie, DO2. We studied 127 postoperative patients who developed ARDS to evaluate the relationship of DO2 to VO2. We found a weak correlation between DO2 and VO2 in the total series (r = 0.49) as well as in several clinical subgroups of patients with ARDS. Moreover, we observed similar relationships in a concurrent group of 218 postoperative patients who did not develop ARDS. We also examined the DO2/VO2 data of individual patients with ARDS to identify instances where flow-dependent VO2 patterns developed into flow-independent VO2 patterns. We were able to identify an apparent plateau in the DO2/VO2 relationships in 29/50 (58 percent) patients where multiple measurements were obtained over a short period of time. Our data are consistent with the concept that the DO2/VO2 relationship in acutely ill early postoperative patients with and without ARDS is affected by antecedent circulatory problems that may lead to tissue hypoxia and tissue oxygen deficiencies that are manifest by flow dependency.


Nasal mask ventilation in acute respiratory failure. Experience in elderly patients.

Nasal mask ventilation (NMV) has been used successfully in chronic restrictive respiratory failure and more recently in acute exacerbations of chronic obstructive pulmonary disease (COPD). This study aimed to evaluate the possible role of NMV in acute respiratory failure (ARF) episodes when mechanical ventilation with endotracheal intubation is questionable. Thirty patients (age, 76 +/- 8.1 years) were treated by NMV during ARF episodes (COPD, 20; other chronic respiratory failure [CRF], 5; chronic heart failure [CHF], 4). All patients were hypoxemic (PaO2, 5.85 +/- 1.62 kPa) and hypercapnic (PaCO2, 8.63 +/- 1.89 kPa) with respiratory acidosis (pH, 7.29 +/- 0.08). In all cases, clinical or physiologic parameters indicated the need for mechanical ventilation, but endotracheal intubation was either not applied because of the age and the physiologic condition of the patients (17 cases) or was postponed (13 cases). NMV was performed using a volume-cycled ventilator and a customized nasal mask. Ventilation was continuous during the first 12 hours and the following nights and was then intermittent during the day. Twenty-one patients improved clinically, within a few hours. Progressive correction of arterial blood gases was observed: PaO2 increased during the first hour, but PaCO2 decreased more slowly. Eighteen patients were able to be successfully weaned from NMV. Twelve patients failed to improve despite NMV: eight of them died and four required endotracheal intubation. There was no difference in the success rate between patients in whom endotracheal ventilation was contraindicated or postponed. Clinical tolerance was satisfactory in 23 patients and poor in seven patients. A return to the respiratory condition was observed in the surviving patients with subsequent discharge from hospital. NMV therefore successfully treated respiratory distress initially in 60 percent of the 30 patients. These results suggest that NMV could be a possible alternative in the treatment of ARF, even in very ill patients, when endotracheal ventilation is controversial or not immediately required.


An interrupter technique for measuring respiratory mechanics and the pressure generated by respiratory muscles during partial ventilatory support.

We evaluated the airway occlusion maneuver as a method to estimate respiratory resistance, respiratory elastance and the pressure generated by respiratory muscles in ICU patients breathing in the PSV mode. The airflow was interrupted at selected flows or volumes during inspiration by a computer-driven rapid occlusion pneumatic valve. The airway occlusion was maintained for 2 to 3 s. From the airway pressure tracing we obtained various measurements of pressure. We then computed the pressure generated by the patient's inspiratory muscles. The method was validated by two different approaches in two groups of patients: the Pes and the CMV protocols. We conclude that the airflow interruption method can be used to measure basic respiratory mechanical parameters in PSV patients. The method also offers an opportunity to evaluate Pmusc,aw and the respiratory work performed by the patient.


Evaluation of a reservoir device for metered-dose bronchodilator delivery to intubated adults. An in vitro study.

We investigated the use of a reservoir device for delivery of a MDI bronchodilator aerosol using a lung model of an intubated, mechanically ventilated adult. Albuterol (Proventil) was delivered with a MDI using three methods. In method 1, the MDI was attached directly onto the ETT using a commercially available actuator/adapter. In method 2, the Monaghan AeroVent reservoir was placed on the inspiratory limb of the ventilator circuit just before the patient Y connector. In method 3, the AeroVent was placed between the patient Y connector and the ETT. Standardized ventilator settings with a Servo 900C were used for all three methods (VE = 9.6 L; respiratory rate = 12 breaths per minute; TI = 20 percent of 1 s). Aerosol drug delivery was measured at the distal tip of the ETT using a spectrophotometric technique. Percentage of amount delivered was calculated from measured delivery of the MDI. The MDI directly on the ETT delivered 7.3 percent of the total dose to the end of the ETT. The AeroVent on the inspiratory limb increased this to 32.1 percent and the AeroVent between the Y connector and the ETT delivered 29 percent. Both reservoir delivery methods delivered significantly more drug than direct placement of the MDI on the ETT (p less than 0.01) but did not differ from each other (p greater than 0.05). Use of the AeroVent reservoir chamber significantly increased bronchodilator delivery by aerosol with an MDI in an adult lung model of an intubated patient on ventilatory support.


The effects of cromolyn sodium in dogs undergoing high-frequency oscillation superimposed on conventional mechanical ventilation.

The effects on gas exchange of superimposition of high-frequency oscillation (HFO) (40 Hz) on conventional mechanical ventilation were investigated in mongrel dogs with eucapnic gas exchange on conventional mechanical ventilation (CMV). The dogs were anesthetized, paralyzed, and ventilated with CMV until stable. Oscillation was then superimposed for 15 min, followed by CMV alone for a further 30 min. During HFO superimposed on CMV (CMV-HFO), the arterial carbon dioxide tension (PaCO2) increased from 43.6 +/- 1.2 mm Hg to 47.2 +/- 1.4 mm Hg (p less than 0.02), whereas the arterial oxygen tension (PaO2) did not change at all. The change was inhibited completely by administration of intravenous cromolyn sodium (CS) (6 mg/kg/min). The mean pulmonary arterial pressure (mPAP), cardiac output (CO), pulmonary capillary wedge pressure (PCWP), and pulmonary vascular resistance (PVR) did not change during the experiment. These results demonstrate that CMV-HFO appears to cause CO2 accumulation and eliminates the impaired O2 transfer, and that these effects are inhibited completely by CS administration.


Pulmonary venous infarction.

Pulmonary venous infarction, although rare, can develop in patients with the various pathologic conditions outlined. The triad of cough, dyspnea, and hemoptysis should raise clinical suspicion. The venous phase of pulmonary arteriography is the best way to document pulmonary venous obstruction, although MR imaging may also prove useful in the future. Treatment of patients with pulmonary venous infarction should be determined on the basis of the obstructing pathologic findings. Antibiotic therapy is important, as evidenced by the early experimental experience with this condition. It may be the only treatment available to patients with idiopathic fibrosing mediastinitis. Pulmonary resection, however, can be accomplished when a localized obstructing lesion is identified.


Diverse roentgenographic manifestations of the rare pulmonary involvement in myeloma.

Roentgenographic manifestations of two cases of pulmonary involvement with myeloma were presented. One showed a nodular mass lesion extending from an extramedullary mediastinal plasmacytoma into the lung parenchyma while the other showed diffuse reticulonodular infiltrate by myeloma cells in association with alveolar septal amyloidosis. These two cases demonstrate the extreme variability of pulmonary involvement by myeloma, which can mimic a solitary tumor or an inflammatory infiltrate.


Lung transplantation in a patient with a prior bone marrow transplant.

A 25-year-old woman with acute lymphoblastic leukemia underwent two bone marrow transplants. She subsequently developed severe restrictive lung disease which was successfully treated with a single lung transplant.


Pulmonary venous infarction secondary to squamous cell carcinoma.

This type of pulmonary venous infarction has not been previously reported, namely: pulmonary vein obstruction from squamous cell carcinoma. Furthermore, this case is unique in that the characteristic pathologic vascular changes observed with pulmonary venous infarction were contrasted with a noninfarcted upper lobe that was removed from the same patient one year later.


Candida albicans purulent pericarditis treated successfully without surgical drainage.

Cures of Candida pericarditis reported in the literature uniformly involved surgical drainage of the pericardial space. We report a patient with purulent pericarditis caused by Candida albicans who was treated successfully with antifungal chemotherapy combined with a single pericardiocentesis that did not completely evacuate the pericardial space. This case indicates that thoracotomy with surgical drainage of the pericardium is not mandatory for successful therapy of Candida pericarditis.


Nonbacterial thrombotic endocarditis. Assessment by transesophageal echocardiography.

Nonbacterial thrombotic endocarditis (NBTE) is difficult to detect antemortem and is often not suspected until embolic events occur. Transthoracic echocardiography is useful in diagnosing NBTE, but it may be limited by suboptimal imaging and resolution. Herein we describe the first reported case of NBTE diagnosed by transesophageal echocardiography. As early detection and treatment may avert significant embolic complications, transesophageal echocardiography should be strongly considered if other techniques are nondiagnostic and clinical suspicion of NBTE remains high.


HIV-associated pericardial effusions.

Following a case of cardiac tamponade in a patient with the acquired immunodeficiency syndrome (AIDS), we examined the frequency and clinical spectrum of pericardial effusions associated with human immunodeficiency virus infection (HIV) at our institution. Of 187 hospitalized patients documented to have pericardial effusions over a one-year period, 14 (7 percent) were known to be HIV-positive at the time of their echocardiograms. One patient presented with a large effusion and cardiac tamponade, three had moderate effusions, and ten had small effusions. The probable effusion etiology was established in four cases and included endocarditis (2), lymphoma (1), and myocardial infarction (1). In hospital mortality was 29 percent (4 of 14). From our study, as well as a growing number of reports in the literature, we conclude that HIV-associated pericardial effusions are frequently seen and that their clinical spectrum is broad.


Treatment of life-threatening primary pulmonary hemosiderosis with cyclophosphamide.

This report describes a five-year-old boy with severe pulmonary hemorrhage caused by primary pulmonary hemosiderosis with cow's milk sensitivity. After failing to respond to corticosteroids and azathioprine, he dramatically improved after being given cyclophosphamide. He worsened after discontinuation of cyclophosphamide on two occasions and improved significantly with its reinstitution. Cyclophosphamide was continued for 14 months without further bleeding or adverse effects. The patient has remained in remission for nearly five years. Cyclophosphamide may be a life-saving alternative therapy for refractory pulmonary hemorrhage with pulmonary hemosiderosis.


Implantable cardioverter defibrillator infection causing constrictive pericarditis.

A case of severe constrictive pericarditis resulting from an indolent Pseudomonas aeruginosa infection of the automatic internal cardiac defibrillator is described. Total explanation of the device was attempted after nine months but was unsuccessful because of dense adhesions under the patch electrodes. The patient subsequently developed clinical and hemodynamic findings of constrictive pericarditis and a second desperate attempt to remove the patches resulted in operative death. Diagnostic modalities for detecting infection of the AICD are reviewed. As soon as there is infection involving any component, the entire lead system and pulse generator should be removed.


Tracheal sounds in upper airway obstruction.

A boy with subglottic narrowing secondary to laryngotracheitis presented with noisy breathing. Acoustic measurements of tracheal sounds at standardized air flows correlated well with the clinical course and with spirometric assessments. This indicates the potential value of respiratory sound characterization in patients with upper airway obstruction.


Dangerous pencils and a new technique for removal of foreign bodies.

Aspirated foreign bodies are important problems during childhood. Some instances may be fatal. Most of the foreign bodies are removed with use of classic instruments like rigid bronchoscopes and foreign body forceps. But sometimes we fail to remove them, particularly aspirated beads and spherical objects. In this case, a Fogarty catheter is helpful. Although we have had many experiences recently we failed to remove one aspirated foreign body which was a pencil cap. We succeeded in removing this pencil cap with a new technique that is explained in this article. We used a Storz transbronchial aspiration biopsy needle and a cotton-carrier stylet to remove the pencil cap.


Single lung transplantation for primary pulmonary hypertension without cardiopulmonary bypass.

We report the first case, to our knowledge, of single lung transplantation for primary pulmonary hypertension carried out without cardiopulmonary bypass. This operation seems to be possible even if the right ventricular ejection fraction is low (0.17) and the pulmonary vascular resistance very high (1,096 dynes.s.cm5). Since 1981, heart-lung transplantation has been successfully performed in patients with primary pulmonary hypertension. If heart-lung transplantation results in resolution of pulmonary hypertension, the incidence of obliterative bronchiolitis is significant in heart-lung transplantation recipients. Single lung transplantation has been performed for end-stage interstitial and obstructive lung disease but has not been considered a good option for primary pulmonary hypertension due to concerns that a single transplanted lung would be unable to cope with the entire blood flow. However, recently single lung transplantation has been performed for primary pulmonary hypertension, the risk of obliterative bronchiolitis remaining unknown. The purpose of this communication is to report one case of single lung transplantation for primary pulmonary hypertension and the feasibility of this operation without the use of cardiopulmonary bypass, if cardiopulmonary bypass is thought to be dangerous.


Prolonged extracorporeal support for ARDS using surface-heparinized equipment.

Severely ill ARDS patients present major supportive challenges when conventional ventilatory support is failing. A patient is described who was treated with venovenous extracorporeal lung support for 28 days, using surface-heparinized circuitry. Her recovery illustrates the potential for salvage of near-terminal ARDS patients when complications of support can be minimized.


Orthostatic and exercise-induced advanced nodal atrioventricular block.

A 69-year-old woman was referred for asthenia and dizziness when walking in the last two months. No clinical abnormalities were found, and sinus rhythm was present when lying down. On orthostatism and walking, advanced AV block developed. Atropine and isoproterenol ameliorated the AV conduction abnormality, suggesting a nodal block. The patient remained asymptomatic after pacemaker implantation.


Polypoid endobronchial lesions. A manifestation of bacillary angiomatosis.

Polypoid endobronchial lesions occurred in a patient with acquired immunodeficiency syndrome (AIDS) with recent fever, skin lesions, lymphadenopathy, lung infiltrates, and pleural effusions. His condition improved with antimicrobials and vincristine. After therapy ceased, skin lesions recurred and gastroesophageal mucosal lesions developed. Bacillary angiomatosis was identified during retrospective analysis of skin and endobronchial biopsy specimens.


Intralobar pulmonary sequestration presenting as congestive heart failure in a neonate.

We recently evaluated a premature infant with intralobar pulmonary sequestration which presented with signs of CHF. The infant initially underwent ligation of a PDA but subsequently developed tachycardia, tachypnea, and a continuous murmur which radiated to the back. The diagnosis of a pulmonary sequestration was suggested by Doppler echocardiography and confirmed by aortography. The sequestration was successfully treated by surgical removal of the involved lobe.


Diagnostic value of pleural fluid cytology in occult Boerhaave's syndrome.

When Boerhaave's syndrome presents with atypical clinical features and eludes prompt diagnosis, delays in surgical therapy increase complications and mortality. We present a patient with occult Boerhaave's syndrome who had nondiagnostic esophageal contrast studies and thoracic computed tomography. Pleural fluid cytologic analysis established the presence of esophageal rupture by detecting undigested food particles.


The threat of resistance to the new oral cephalosporins.

Phenotypic resistance to beta-lactam antibiotics is mainly due to the prevalence of beta-lactamases. The most common enzymes responsible for resistance to aminopenicillins and older (1st generation) cephalosporins are the TEM-1, TEM-2, OXA-1 and SHV-1 enzymes, all of which are plasmid-mediated. The recent development of oral cephalosporins sharing structural features and an antimicrobial spectrum comparable to that of 3rd-generation cephalosporins has provided highly active compounds for the management of outpatient infections. Two principal mechanisms, however, may cause resistance to these new compounds: the overproduction of chromosomally encoded beta-lactamases with predominating cephalosporinase activity, and the recently observed extended-spectrum beta-lactamases. The overproduction of chromosomally mediated beta-lactamases has been observed only in some species (Enterobacter cloacae, Citrobacter freundii, Serratia spp.) which cause mainly nosocomial infections and are therefore of minor importance in outpatients. The extended-spectrum beta-lactamases TEM-3 to TEM-12 and SHV-2 to SHV-7 have been observed in various countries, they derived from the original enzymes by point mutations and occurred in intensive-care units. These enzymes may cause resistance to 3rd-generation cephalosporins including the recently developed orally active compounds. Moderate resistance to cefetamet is observed only in strains producing either the TEM-3 or the TEM-4 enzyme, whereas the prevalence of the other enzymes is of no consequence for the activity of cefetamet. Consequently, cefetamet will not exhibit a marked selection pressure favoring the spread of extended-spectrum beta-lactamase-producing strains.


Clinical studies in pediatric respiratory-tract infections: what is desirable, feasible, or simply misleading.

In recent years, attempts have been made to make the regulatory requirements for clinical studies more uniform, and much has been discussed on the issue of good clinical practice. There is no doubt that clinical trials involving new drugs have to be conducted according to the highest standards. However, ideal design is not always feasible or ethical. The ideal design for efficacy studies demands randomization, double-blind comparisons, adequate group size, specification of the type of patients and isolated organisms. The present paper points out some difficulties regarding these points when studying cephalosporins in pediatric respiratory-tract infections, and proposes some solutions.


The pharmacokinetics of new oral cephalosporins in children.

Differences in the pharmacokinetic parameters of cephalosporins between children and adults may be predictable on the basis of the level of maturation of the physiologic processes involved in drug disposition. It appears that the most important of these factors (gastrointestinal, renal and hepatic function) are reasonably mature by the age of 1 year. As a result, the primary difference between adults and children relates to size and body composition. Comparable bioavailability is expected in children and adults. However, absolute values for systemic clearance (ClS) and volume of distribution (VSS) will be lower in children. It has been suggested that ClS in children is reduced in proportion to body surface area. This may also be true for the VSS of the cephalosporins since they distribute primarily into the extracellular fluid space which has been shown to be similar in children and adults when adjusted for surface area. If both ClS and VSS are proportional to surface area, half-life will be similar in adults and children. Data with cefetamet generally support these principles. Clearance normalized for body surface area averaged 69.3 ml/min/m2 in children aged 3-7 years, 64.9 ml/min/m2 in children of 8-12 years and 68.9 ml/min/m2 in adults. The VSS remained somewhat smaller in children than adults even after correction for surface area. Bioavailability and elimination half-life in children were similar to values in adults. Data with other new cephalosporins are limited, but differences between children and adults in bioavailability and half-life appear to be insignificant.(ABSTRACT TRUNCATED AT 250 WORDS)


Cefetamet pivoxil in pediatric otitis media.

Cefetamet, an oral 3rd-generation cephalosporin, was investigated in 40 children with acute otitis media in a comparative randomized trial. The efficacy of 20 mg/kg cefetamet syrup in 20 patients was compared with that of 20 mg/kg cefaclor in another 20, both drugs being given orally twice daily for 7 days. Tympanocentesis was performed for every child before the initiation of antimicrobial treatment. After 7 days treatment with cefetamet pivoxil, clinical cure was obtained in 12 patients, 3 were failures and 5 could not be assessed. In the cefaclor group, 10 patients were cured, 1 improved and 9 were failures. No severe adverse events were observed with either drug.


Clinical trials on pediatric lower-respiratory-tract infection: results and comments with cefetamet pivoxil.

A total of 30 pediatric patients suffering from lower-respiratory-tract infections were admitted to a three-arm, open, randomized study comparing two different doses of cefetamet pivoxil (either 10 or 20 mg/kg b.i.d.; groups A and B, respectively) with the standard cefaclor treatment (10 mg/kg t.i.d.; group C) for 7-12 days. The 30 cases were randomly assigned to the three treatment arms which were comparable with regard to demographics as well as to diagnosis on admission and concomitant medication. The children ranged from 1.08 to 12 years in age, and comprised 18 males and 12 females, with a weight range of 11-42 kg. As is to be expected in these patients, bacteriology was mostly not assessable. The overall clinical outcome was cure in 9, 8 and 9 cases, respectively, and improvement in 1, 2 and 0 cases, respectively. In the cefaclor group 1 patient failed to respond. Signs and symptoms of disease improved significantly in the three treatment groups; there were no intergroup differences. Vital signs (morning and evening temperature and pulse rate) improved in parallel. Radiological results had improved by the end of treatment in 9/10 patients in group A, in 10/10 patients in group B, and in 9/10 evaluable patients in group C. Mild to moderate nausea or vomiting were each reported in 1 patient in group A. Platelet increase was reported as a mild adverse event in 2 patients in each of the cefetamet pivoxil groups and in 4 patients given cefaclor.(ABSTRACT TRUNCATED AT 250 WORDS)


Comparative study of cefetamet pivoxil and penicillin V in the treatment of group A beta-hemolytic streptococcal pharyngitis.

The efficacy of cefetamet pivoxil (20 mg/kg and 10 mg/kg b.i.d.) was investigated in an open, prospective, randomized, comparative multicenter trial involving 148 children suffering from group A beta-hemolytic streptococcal (GABHS) pharyngo-tonsillitis. Phenoxymethylpenicillin given for 10 days was used as the reference drug and resulted in 15% treatment failures. After treatment with cefetamet pivoxil 20 mg/kg b.i.d., 2 failures (5.8%) were observed in 34 patients treated for 7 days and 2 (6%) in 33 patients after 10 days treatment. In 8 children treated with cefetamet pivoxil 10 mg/kg b.i.d. for 10 days, 7 were cured and 1 relapsed in the late follow-up. Recruitment for this dosage group is being continued. No serious adverse events occurred. Cefetamet pivoxil, given b.i.d., can be considered an alternative to phenoxymethylpenicillin in the treatment of GABHS pharyngo-tonsillitis.


Myogenesis in the mouse.

The first striated muscle to form during mouse embryogenesis is the heart followed by skeletal muscle which is derived from the somites. The expression of genes encoding muscle structural proteins and myogenic regulatory sequences of the MyoD1 family has been examined using 35S-labelled riboprobes. In the cardiac tube, actin and myosin genes are expressed together from an early stage, whereas in the myotome, the earliest skeletal muscle, they are activated asynchronously over days. They are not expressed in the somite prior to myotome formation. One potential muscle marker, carbonic anhydrase III, is expressed in early mesoderm and subsequently in the notochord, similarly to the Brachyury gene. The myogenic sequences are not detectable in the heart. In the myotome they show distinct patterns of expression; this is discussed in the context of their role as muscle transcription factors. myf-5 is the only myogenic factor sequence present in the somite prior to muscle formation and thus is potentially involved in an earlier step of muscle determination. It is also present in the early limb bud, but the status of myogenic precursor cells in the limb in this context is less clear.


Development of the skeletal system.

The analysis of the development of the skeletal system has been greatly facilitated by the availability of a large number of mouse mutants with skeletal defects. Whereas for many of these mutants a description of the main phenotypic abnormalities is known, molecular insight into the ontogeny of the skeletal system is limited. One of the few skeletal mutants for which the molecular basis is known is undulated. These mice have a defect in the differentiation of the sclerotome and Pax-1, a mouse paired-box containing gene, has been identified as a candidate gene for this mutation. A molecular analysis of three independent undulated alleles revealed that in each case the Pax-1 gene is affected. One of the alleles could be classified as a null allele, in which the Pax-1 gene is deleted. A phenotypic analysis shows that Pax-1 is required for proper differentiation of intervertebral discs and vertebral bodies.


Development of the left-right axis.

Left-right is not an axis in the conventional sense but rather two mirror-image proximodistal axes, upon which a quantal piece of positional information (leftness or rightness) is superimposed for laterally asymmetric organ development. We are attempting to establish the stages at which left-right is specified and determined, but this is complicated by the apparent loss of normal handed development in embryos that are cultured from pre-neural plate stages. Experiments suggest that left-right is determined by the first somite stage. The loss of normal left-right development in early cultures is probably not due to removal of some maternal signal, even though embryos do develop in vivo with their axes in a specific orientation relative to the uterus. The fact that there are two random embryonic axis orientations, 180 degrees opposed to one another, and that the axes of the two uterine horns are mirror-images of each other make it unlikely that the uterus could impart a sense of left-right to the embryo. The right ovary produces more eggs than the left one; this is reversed in iv/iv situs inversus mice. Analysis of iv/iv mice shows a correlation of left-right abnormalities with sex and close relationships between the abnormal left-right development of some organs, for example the heart and spleen, that have no obvious developmental connection.


The role of Sry in mammalian sex determination.

The testis-determining gene is the Y-linked gene responsible for initiating the developmental pathway leading to testis formation in males. A strategy based on determining the precise chromosomal location of this locus has been used to clone a new gene which has been called SRY in humans (Sry in mice). A variety of studies now show that this is indeed the testis-determining gene. Sry has a spatial and temporal pattern of expression which correlates with the initiation of testis differentiation. The amino acid sequence encoded by the gene suggests that the protein may function as a transcription factor, which fits well with models of sex determination. Some cases of XY sex reversal in humans and mouse have been attributed to mutations in SRY/Sry, indicating that it is normally necessary for testis determination. The finding that a genomic fragment carrying Sry can cause male development in XX mice has proved that Sry is the only gene from the Y chromosome necessary for testis determination.


Epithelial-mesenchymal interactions in murine organogenesis.

Reciprocal, sequential interactions between embryonic epithelial and their mesenchymal stroma guide the cytodifferentiation and organization of both components. These morphogenetic interactions and their consequences are examined in two model systems in vitro: the mouse metanephric blastema and the tooth rudiment. Experimental approaches include dissection and recombination of the interacting tissues, localization of molecular changes by immunohistology and in situ hybridization. An early response of the mesenchyme is increased proliferation of cells in the vicinity of the epithelial inductor and their subsequent aggregation (condensation). In the kidney model disruption of this aggregation or prevention of assembly of the programmed cells results in impaired cytodifferentiation. If the cells are allowed to reaggregate, a phenotype is expressed not unlike that seen in normal in vivo conditions. Our present interest is focused on the early metabolic events associated with the condensation phenomenon. The cell surface proteoglycan syndecan and the matrix glycoprotein tenascin are expressed in the condensed mesenchyme and may mediate cell-matrix interactions. The expression patterns of certain growth factors suggest functions in signal transduction.


The Wnt family of cell signalling molecules in postimplantation development of the mouse.

The mammalian Wnt gene family consists of at least ten members, all of which share a common structure. The N-terminus encodes a putative signal peptide sequence, suggesting that Wnt proteins are secreted. A number of absolutely conserved cysteine residues imply that inter- or intramolecular disulphide bonding is important to Wnt protein function. Wnt RNAs are localized to discrete regions of the postimplantation embryo and fetus, particularly within the developing central nervous system. Studies on Wnt gene expression strongly suggest that Wnt-mediated signalling is likely to be an important aspect of mouse development. One member of the family, Wnt-1, has been studied in some detail. By generating mutant alleles, we have demonstrated that Wnt-1 regulates regional development of the central nervous system at early somite stages. There is circumstantial evidence that some aspects of the pathway through which Wnt-1 action is mediated may be evolutionarily conserved. We propose that the Wnt family plays a major role in cell-cell interactions in the mouse.


The TGF-beta-related DVR gene family in mammalian development.

The genes that encode the bone morphogenetic proteins and the Vg-related proteins are mammalian members of a group of TGF-beta-related genes, designated the DVR family, that includes the decapentaplegic gene of Drosophila and the Vg1 gene of Xenopus. Members of the DVR (decapentaplegic-Vg-related) family have been implicated in diverse processes during development, particularly in epithelial-mesenchymal interactions. The results of our in situ hybridization studies with postimplantation mouse embryos provide evidence for the involvement of DVR family members, particularly DVR-2, DVR-4 and DVR-6, in specific inductive interactions during the development of many organs, including the limb, the whisker follicle and the heart.


Use of embryonic stem cells to study mutations affecting postimplantation development in the mouse.

The generation and analysis of insertional mutations that perturb early postimplantation development provide a means to identify genes required at this stage of embryogenesis. We have been studying two independently generated insertional mutations termed 413.d and H beta 58 that result in early postimplantation lethality. Each mutation is associated with a distinct phenotype. 413.d mutant embryos become profoundly abnormal around the time of gastrulation: no identifiable embryonic axis or mesodermal structures are formed. H beta 58 mutant embryos proceed further in development, forming a relatively normal anteroposterior axis before developmental arrest occurs. We isolated embryonic stem cell lines homozygous for each of these mutations and assessed their differentiation abilities and developmental potential in vitro and after their introduction into wild-type blastocysts. From these studies we conclude that the 413.d mutation acts in a non-cell-autonomous fashion: mutant cells appear capable of participating, in conjunction with wild-type cells, in the formation of derivatives of all three primary cell lineages of the embryo. H beta 58 mutant embryonic stem cells are clearly pluripotent but they appear to be more restricted in their developmental potential, suggesting that the H beta 58 gene product may be required by specific tissues of the embryo.


Genetic manipulation of the mouse via gene targeting in embryonic stem cells.

Gene targeting applied to totipotent embryonic stem (ES) cells is a very powerful means of creating highly specific mutations of genes in the mouse. The successful application of this technology is however constrained by both the types of mutations that can be generated at a target locus and the ability to reconstruct a germline chimera from the manipulated cells. We have developed two cell lines that can be routinely transmitted through the germline of chimeras after cloning and prolonged selection in tissue culture. We have also established a variety of methods for generating non-selected mutations at the X-linked hprt locus in ES cells. Our observations at this locus have enabled us to generate successfully a subtle mutation at the non-selectable Hox-2.6 locus.