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Biomedical subjects

J Weinberg

Publications and source records attributed to J Weinberg.

At least 73 records · Page 4Linked to original sources
PubMed1996

Fetal ethanol exposure alters pituitary-adrenal sensitivity to dexamethasone suppression.

The present study investigated the hypothesis that a deficit in feedback inhibition of the hypothalamic-pituitary-adrenal (HPA) axis may underlie the hormonal hyperresponsiveness seen in fetal ethanol-exposed rats. Male and female Sprague-Dawley rats from prenatal ethanol (E), pair-fed (PF) and ad lib-fed control (C) treatment groups were tested in adulthood. The effects of dexamethasone (DEX) blockade on basal and stress corticosterone (CORT) levels and stress adrenocorticotropin (ACTH) levels were examined over a 36-h period. Stress CORT and ACTH levels after DEX administration at the trough (AM) and peak (PM) of the CORT circadian rhythm were compared. DEX administration significantly suppressed both resting and stress levels of CORT and ACTH in all animals, regardless of prenatal treatment. Importantly, E animals did not differ from PF and C animals in basal CORT. However, E males and females had significantly higher stress levels of CORT and/or ACTH than PF and C animals, and further, showed differential responsiveness following DEX administration depending on the time of day when testing occurred. At the trough of the CORT circadian rhythm. E males did not differ from PF and C males, whereas E females had increased stress levels of CORT compared to PF and C females. In contrast, at the peak of the circadian rhythm, E males showed increased stress levels of CORT but not ACTH, whereas E females showed increased stress levels of both CORT and ACTH compared to males and females in respective control groups. These data support the hypothesis that E animals may exhibit deficits in HPA feedback inhibition compared to controls and suggest a sex-specific difference in sensitivity of the mechanism underlying HPA hyperresponsiveness.

Adrenocorticotropic Hormone↗
PubMed1996

The organisms reported to cause infective myocarditis and pericarditis in England and Wales.

It is difficult to acquire an overall perspective of the range of organisms responsible for infective myocarditis or pericarditis, and their relative importance, as most studies have involved only case reports or case series of a single organism. This study analyses reports to the Communicable Disease Surveillance Centre, of the Public Health Laboratory Service. Reports where myocarditis or pericarditis was included as the main clinical features between 1990 and 1993 were studied. Between 1990 and 1993, 368 cases of myocarditis and/or pericarditis were reported to CDSC. Viruses were reported to cause 253 (69%) cases, bacteria were responsible for 49 (13%) cases, mycoplasma for 32 (9%) cases, chlamydia for 16 (4%) cases and Mycobacterium tuberculosis for nine (2%) cases. Infection with coxsackie B virus was most frequently associated with a mixed picture of myo/pericarditis, whereas influenzae virus was associated with pericarditis or myocarditis alone. This information will provide clinicians with details of the more likely pathogens responsible for these conditions.

England↗
PubMed1996

Electromyographical evidence for exercise-induced diaphragm fatigue in patients with chronic cervical cord injury or prior poliomyelitis infection.

UNLABELLED: The purpose of this study was to determine, in exercising patients, how much diaphragm force increases before electromyographical evidence of diaphragm fatigue occurs. The study was performed in ten male patients with complete cervical cord injury (CCI) at the C5 to C8 levels, and five male patients with prior poliomyelitis infection (PPI) requiring chronic treatment with intermittent positive pressure ventilation (IPPV) at night. We studied the time course of the diaphragmatic tension-time index (TTdi), the centre frequency (CFdi) of the diaphragm electromyogram (EMGdi) power spectrum, and the ventilatory parameters, during steady-state submaximal arm/leg exercise. During exercise, early signs of diaphragm fatigue were present in seven out of 10 CCI patients and in four out of five PPI patients, as indicated by a reduction in CFdi. The increase in TTdi achieved before reductions in CFdi occurred was twofold in both the CCI and PPI patients. All patients except for the PPI patients, who demonstrated a reduction in CFdi, showed an increase in minute ventilation (VE), achieved by increasing both their tidal volume (Vt) and the breathing frequency (fb). The PPI patients demonstrating reductions in CFdi during exercise also increased their VE however, this was achieved by increasing fb while Vt remained constant. Following the reductions in CFdi, the CCI patients further increased their TTdi throughout the exercise test, while the PPI patients reduced their TTdi values. IN CONCLUSION: (1) During exercise, electromyographical evidence for diaphragmatic fatigue frequently occurred in the CCI and PPI patients studied; (2) Compared to the eightfold increase in TTdi seen in healthy subjects before reductions in CFdi occur, the TTdi values increased only two-fold before electromyographical evidence of diaphragm fatigue was present in these patients; (3) There is a clear discrepancy between the CCI and PPI patients who demonstrate electromyographical evidence of diaphragm fatigue, in terms of their ventilatory and TTdi responses.

Adult↗
PubMed1996

The effect of trunk support on performance during arm ergometry in patients with cervical cord injuries.

Earlier studies have shown that the diaphragm might have a postural function that could interfere with its respiratory function during arm cycling in patients with cervical cord injuries with impaired elbow extension. The purpose of this study was to evaluate the effect of trunk support on working performance in such patients. Ten patients with low-cervical-cord injuries performed an arm ergometer test without and with trunk support with at least one week between the tests. The work load averaged 30 (20-50) Watt. Oxygen uptake at steady state averaged 0.71 +/- 0.09 l/min without trunk support and 0.64 +/- 0.10 l/min with trunk support, P < 0.05. There was no difference in blood lactate without or with trunk support. Maximum performance time averaged 8.3 +/- 4.3 min without trunk support and 19.5 +/- 8.8 min with trunk support, P < 0.01. Oxygen saturation tended to decrease during work and returned to resting values after termination. This study showed that trunk support during arm ergometry in cervical-cord-injury patients with impaired elbow extension decreased the energy cost during sub-maximal work and increased the time to perform work. The results indicate that trunk stabilisation might improve performance of activities of daily living and that it should also be considered during exercise affecting the postural balance of these patients.

Adult↗
PubMed1996

Diaphragm function in patients with cervical cord injury or prior poliomyelitis infection.

Diaphragm function was evaluated in cervical cord injury patients (CCI), 1-3 years after injury (CCI(1-3)) and 10 years or more after injury (CCI(> or = 10)), as well as in a group of prior poliomyelitis infection patients (PPI), requiring intermittent positive pressure ventilation (IPPV) for about 6 h per night. Measurements included transdiaphragmatic pressure swings (delta Pdi) at rest, during maximal inspiratory efforts against closed airways (delta Pdi(max)) and during sniff manoeuvres (ie maximal inhalation through the nose, delta Pdi(sniff)), vital capacity normalized to age and height (VC(%pred)), tidal volume (Vt), relative inspiratory time (Ti/Ttot), breathing frequency (f(b)), and the tension-time index of the diaphragm (TTdi = delta Pdi/delta Pdi(max) x Ti/Ttot). The median VC(%pred) was 50% in the CCI(1-3) group and 57% in the CCI (> or = 10) group, but only 28% in the PPI group. Delta Pdi(max) values were similar for the CCI(1-3) (11.8 kPa) and CCI(> or = 10) (11.9 kPa) groups but were lower (71. kPa) in the PPI group. Due to the reduction in delta Pdi(max), the PPI group had higher delta Pdi/delta Pdi(max) values than the CCI groups, however, the TTdi was similar amongst the different groups studied. A submaximal exercise test in five cervical cord injury patients and in five polio patients with similar delta Pdi(max), delta Pdi(sniff) and TTdi values at rest revealed clear group differences with respect to force development, in that CCI patients showed significant increases in TTdi, while PPI demonstrated only minor changes. In CCI patients, an increase in ventilation was accompanied by an increase in delta Pdi/delta Pdi(max) while in contrast, the PPI patients showed no increase in delta Pdi/delta Pdi(max). We conclude that CCI patients, both recently and previously injured, have a similar maximal inspiratory force and are less impaired than the PPI patients. The TTdi at rest is similar in all groups, but the PPI patients react to inspiratory loads with little increases in TTdi, while the CCI patients increase their TTdi above fatiguing (0.15) levels. The different behaviours may be linked to loss of sensory pathways in the CCI patients.

Adult↗
PubMed1996

Fetal ethanol exposure: hypothalamic-pituitary-adrenal and beta-endorphin responses to repeated stress.

Previous studies provide evidence that fetal ethanol exposure induces hypothalamic-pituitary-adrenal (HPA) and pituitary beta-endorphin (beta-EP) hyperresponsiveness to acute stressors. The present study demonstrates significant effects of in utero ethanol exposure on the parallel response patterns of the HPA axis and the pituitary beta-EP system to repeated exposures to a stressor, restraint stress, and indicates sex differences in response. Together, data from the two experiments indicate that, after repeated restraint exposures, fetal ethanol-exposed (E) males and females both show significantly increased plasma levels of adrenocorticotropin (ACTH), and E males also show significantly increased plasma levels of beta-endorphin-like immunoreactivity (beta-EPLIR), compared with their respective pair-fed and control counterparts. Marginal increases in the corticosterone response of E males and the beta-EPLIR response of E females, compared with their controls, were also observed. In addition, delayed or deficient habituation to restraint stress was observed in the beta-EPLIR response of E males and the ACTH response of E females. These data demonstrate that fetal E-exposed males and females both exhibit hormonal hyperresponsiveness and/or deficits in recovery after repeated exposures to restraint stress, but that the patterns of response may differ depending on the number and duration of restraint exposures, the time course measured, and whether the endpoint measured is corticosterone, ACTH, or beta-EPLIR. In addition, the finding that E and pair-fed animals both differed from their respective controls in certain developmental and hormonal measures suggests that prenatal nutritional factors may play a role in mediating some of the changes that are observed.

Adrenocorticotropic Hormone↗
PubMed1996

Effect of maternal ethanol consumption on maternal and fetal calcium metabolism.

Alcohol consumption can have deleterious effects on both adult and developing bone. The mechanism(s) by which alcohol affects bone, however, is unknown. This study investigated the possibility that alcohol affects bone by alterations in calcium (Ca) metabolism. Female rats were fed lab chow ad libitum (C, Control) or a liquid diet with (E, Ethanol) or without (PF, Pair-Fed) ethanol. After 2 weeks on their respective diets, the rats were bred and the experimental diets continued throughout gestation. Blood (dams only) and tissue were collected on day 21 of gestation. The Ca content of maternal bone showed a trend toward a decrease in E and PF compared with C dams. Ionic Ca (iCa) levels were decreased in the blood of the E compared with PF and C dams. Serum parathyroid hormone levels were elevated in the E compared with C dams, consistent with the low iCa levels. Serum levels of 1,25(OH)2D, however, were elevated only in the PF dams. Mean fetal body weight and fetal skeletal ossification were reduced in the E compared with PF and C groups, but no group differences were found in fetal Ca content. These results indicate that maternal ethanol consumption compromised the ability of the dam to regulate her blood iCa levels, possibly partly due to a failure to increase 1,25(OH)2D levels. The delays in skeletal development observed in the ethanol exposed fetuses, however, do not appear to result from impaired placental Ca transfer.

Animals↗
PubMed1996

Retrograde percutaneous gastrostomy and gastrojejunostomy in 505 children: a 4 1/2-year experience.

PURPOSE: To evaluate a technique of retrograde insertion of gastrostomy and gastrojejunostomy tubes with radiologic guidance in children. MATERIALS AND METHODS: During a 4 1/2-year period, 511 patients underwent attempted insertion of gastrostomy or gastrojejunostomy tubes. Patients' ages ranged from premature to 18.6 years (mean age, 3.8 years), and weight range was 0.8-86.0 kg (mean weight, 12 kg). The charts of 453 patients were reviewed. RESULTS: Placement was unsuccessful in six patients because of colonic interposition (n = 2), microgastria (n = 2), or hepatosplenomegaly (n = 2). Initial placement was a gastrostomy tube in 436 patients and a gastrojejunostomy tube in 69 patients. Sixty-eight gastrostomy tubes were converted to gastrojejunostomy tubes. Early complications (< 30 days) included skin infection (n = 11), stoma irritation (n = 20), and tube dislodgment (n = 6). Late complications included stoma irritation (n = 29), skin infection (n = 23), tube leakage (n = 14), and discomfort during feeding (n = 15). Two complications necessitated surgery: extragastric misplacement and small-bowel transgression. There were no tube-related deaths. CONCLUSION: Percutaneous retrograde placement of gastrostomy or gastrojejunostomy tubes safely and effectively provides long-term nutrition for children. A team approach is essential to provide service to this cumulative population.

Adolescent↗