Search PubMed⌕ Search

Biomedical subjects

M H Collins

Publications and source records attributed to M H Collins.

At least 55 records · Page 3Linked to original sources
PubMed1993

Placentas and foetal health.

The placenta provides many critical services to the developing foetus. Proper placental implantation, growth and function are necessary for normal foetal growth and development. Placental structure varies widely among species but all mammalian placentas have a convoluted materno-foetal interface that may be quite simple or highly complex; the more complicated interdigitations tend to characterise smaller placentas that have limited areas of contact between the placenta and the endometrium. The intimacy of the contact between maternal and foetal tissue varies from apposition only, as in the equine placenta, to invasion of maternal vessels by foetal cells, as in man. Abnormalities identified in the human placenta provide insight into maternal and foetal diseases that affect pregnancy outcome.

Animals↗
PubMed1992

Acquired coarctation of the aorta.

Coarctation of the aorta is usually caused by a congenital narrowing of the aorta. This report describes two children who developed hypertension secondary to an acquired coarctation of the aorta. In one patient the coarctation was temporally related to umbilical artery catheterization and was associated with thrombosis and aneurysmal dilatation of the aorta. In the second patient, the coarctation occurred after surgical aortotomy during the removal of an intrathoracic neuroblastoma. Patients who have interventional damage to the aorta should be periodically examined for the appearance of a coarctation. Although an acquired coarctation of the aorta is an infrequent complication of invasive or surgical procedures, it should be identified since it represents a remediable cause of hypertension in children.

Aortic Coarctation↗
PubMed1991

Recurrent herpes gestationis with postpartum flare: a case report.

A case of herpes gestationis recurring in each pregnancy, with a postpartum flare-up in the last pregnancy, is described. The diagnosis was confirmed by skin biopsy. The first pregnancy ended in a term stillbirth, but there were favorable outcomes in four subsequent pregnancies. Histopathologic examination of the placentas of the last three pregnancies revealed varying grades of villositis. Symptoms improved with oral corticosteroids.

Adult↗
PubMed1991

Eosinophilic cystitis in children.

Eosinophilic cystitis is an uncommon inflammatory disorder of the urinary bladder which causes irritative voiding symptoms and may mimic rhabdomyosarcoma radiographically. In children, eosinophilic cystitis has been previously reported to be self-limiting and requires no specific therapy. Reported herein is a case of a nine-year-old girl in whom eosinophilic cystitis recurred following antireflux surgery, raising the question of an association of eosinophilic cystitis with local trauma such as bladder surgery. Consideration should be given to pretreatment with steroids and antihistamines prior to surgery in these patients.

Child↗
PubMed1991

Cystic adrenal masses in the neonate associated with hemihypertrophy and the relation to the Beckwith-Wiedemann syndrome.

We report 2 cases of unilateral, multilocular, cystic adrenal masses in neonates. Both patients demonstrated somatic hemihypertrophy, which is considered to have the same implications as the Beckwith-Wiedemann syndrome in terms of tumor risk. Pathological examination showed multiple, adrenal cysts without evidence of tumor or routine adrenal hemorrhage. This finding appears to represent a previously unreported association between the spectrum of hemihypertrophy/Beckwith-Wiedemann syndrome and benign cystic adrenal disease.

Adrenal Gland Diseases↗
PubMed1990

Early detection of caudal regression syndrome with transvaginal scanning.

High-resolution transvaginal ultrasonography may recognize structures in the first- and early second-trimester fetus. In a patient with pregestational diabetes, caudal regression syndrome in the fetus was diagnosed using transvaginal ultrasonography. At 9 weeks of gestation, a shortening of the crown-rump length and a protuberance of the lower spine suggested caudal regression syndrome. By 17 weeks of gestation, the diagnosis was made with certainty. The transvaginal approach has changed the role of first-trimester ultrasound in the diabetic pregnancy. We suggest that transvaginal ultrasonography be used for purposes of accurate dating and for early detection of diabetic embryopathy, particularly in patients with poor periconceptional glycemic control.

Adult↗
PubMed1989

Lymph node hemangioma.

Lymph node hemangiomas are rare lesions. There have been two previous articles on the subject in the literature. We describe another case in which a lymph node was surgically removed from the inguinal region of a 4 1/2-year-old boy, with a five-month history of a right-sided groin mass. The literature was reviewed, regarding some vasoformative benign lymph node lesions, and a general working classification of these lesions is listed, as we attempted to recognize possible patterns in reactive-proliferative processes and separate them from true neoplasms with hamartomatous features.

Child, Preschool↗
PubMed1987

The effect of prolonged oligohydramnios on fetal lung development, maturation and ventilatory patterns in the newborn guinea pig.

We drained the amniotic fluid surrounding guinea pig fetuses between days 45 and 65 of gestation (term is 67 days). The fetuses were delivered by Cesarean section and the impact of prolonged oligohydramnios on lung growth, maturation and postnatal ventilatory pattern was measured. Untouched littermate fetuses served as controls. Neither fetal body, liver nor brain weights were significantly affected by the experimental situation. When expressed in percent of control values, lung weight (63%), lung/body weight ratio (70%), lung volume (67%), total lung DNA content (63%) and lung DNA per gram of fetal weight (71%) were all significantly less following amniotic fluid drainage, confirming the diagnosis of lung hypoplasia. Disaturated phosphatidylcholine content per gram of lung tissue and total lung glycogen content were not affected by the procedure, indicating that the maturity of the hypoplastic lungs was not delayed. When measured 4 to 6 hours after birth, tidal volume was significantly less (62%) and respiratory frequency was significantly more (137%); however, minute ventilation per unit of body weight was not significantly changed. This animal model of sublethal lung hypoplasia could become useful to study the potential for, and the kinetics of, postnatal catch-up lung growth about which little is known.

Amniotic Fluid↗
PubMed1986

Morphometric analysis of the growth of the normal fetal guinea pig lung.

The structural development of the fetal guinea pig lung is described and quantified morphometrically in this report. At 35 days gestation the lung is in the pseudoglandular phase of growth, by 40 days it is in the canalicular phase, and at 50 days the saccular growth phase has begun. At term (67 days), the fetal guinea pig lung appears mature. From the beginning of the canalicular to the end of the saccular phases, the correlation coefficient between lung volume and gestational age is +.98, between internal surface area and gestational age is +.94 and between total number of saccules and gestational age is +.97. Internal surface area (ISA) correlates closely with lung volume (r = +.99) and the correlation coefficient between total number of saccules and lung volume is +.98. At term, lung volume is 4.22 ml. ISA is 0.5 M2, and total number of saccules is 253 million. Parenchymal growth is achieved by increases in both number and size of airspaces in the canalicular phase, primarily by increases in number during the early saccular phase and largely by increases in airspace size near term. The total length of parenchymal elastic tissue increases from 223 M at 45 days gestation to 5,253 M at term. Elastic tissue fibers first appear in the parenchyma of the fetal guinea pig lung during the canalicular phase, when the rate of saccule formation is high. The quantitative increase in elastic tissue correlates closely with the increase in the total number of saccules from day 45 to day 60 of gestation (r = +.99). The rate of elastic tissue growth increases sharply in the late saccular phase, coinciding with the period of greatest saccular expansion. These data suggest an interdependent relationship between saccular growth, i.e., proliferation and expansion, and the development of lung parenchymal elastic tissue.

Animals↗
PubMed1986

Diaphragmatic activity is a determinant of postnatal lung growth.

To test the hypothesis that activity of respiratory muscles determines regional growth of lung parenchyma, we studied the effects of unilateral diaphragmatic paralysis on contralateral/ipsilateral lung growth in cats and piglets. Five 10- to 12-wk-old cats and five 8-wk-old piglets underwent unilateral diaphragmatic paralysis by thoracic and cervical phrenectomy, respectively. Five to seven weeks after surgery, when the cats were killed for studies of lung growth, gain in body weight was the same as in five sham-operated controls. At this time, mean pleural pressure ipsilateral to the paralyzed hemidiaphragm was the same as contralateral mean pleural pressure during tidal breathing, and values did not differ from controls. However overall functional residual capacity was lower in the phrenectomized cats (35 +/- 4 ml) than in the controls (55 +/- 11 ml, P less than 0.01). Growth of contralateral lungs relative to ipsilateral lungs was greater in the phrenectomized cats than in the controls, as shown by ratios of contralateral/ipsilateral wet lung weight (1.44 vs. 1.34, P less than 0.01), maximum inflation volume (1.53 vs. 1.33, P less than 0.05), and total protein content (1.45 vs. 1.26, P less than 0.05). Ratios of total protein to DNA and RNA to DNA were unchanged. One week after surgery in the piglets, the ratio of contralateral/ipsilateral wet lung weight was increased (1.61 vs. 1.29, P less than 0.01) and total weight of both lungs was reduced. We conclude that regional growth of lung parenchyma by cell proliferation depends in part on regional distribution of respiratory muscle activity.

Animals↗
PubMed1986

Oligohydramnios-induced lung hypoplasia: the influence of timing and duration in gestation.

We drained amniotic fluid for periods of 5 and 10 days at various times in gestation between days 40 and 55 in the guinea pig (term is 67 days). We analyzed the impact of this procedure on fetal lung growth and used untouched littermate fetuses as controls. During the canalicular stage of lung development, total lung DNA per gram of fetal weight was significantly reduced after only 5 days of oligohydramnios and the percent change did not vary between the two consecutive 5-day periods studied (period A, days 40 to 45, delta of -0.047 mg, p = 0.004; period B, days 45 to 50, delta of -0.042 mg, p = 0.002). The impact of the same duration of oligohydramnios on lung growth later in gestation, during the terminal sac stage of lung development, was less (period C, days 50 to 55, delta of -0.027 mg, p = 0.097). This reduction in effect between period A or B and C was significant at the 0.05 level using a one-way analysis of variance. Two overlapping 10-day periods were also studied. In both experiments, the percent changes in lung DNA per gram of fetal weight between experimental and littermate controls were significant (period D, days 40 to 50, delta of -0.072 mg, p = 0.001; period E, days 45 to 55, delta of -0.047 mg, p = 0.001). The inhibitory effect of oligohydramnios on lung growth was more marked in period D than E (significant at the 0.05 level).(ABSTRACT TRUNCATED AT 250 WORDS)

Amniotic Fluid↗
PubMed1986

Morphometry of hypoplastic fetal guinea pig lungs following amniotic fluid leak.

Deficient quantity of amniotic fluid causes fetal guinea pig lung hypoplasia. Oligohydramnios that lasts only 5 days in early gestation is sufficient to reduce fetal lung growth significantly. We quantitated lung structural alterations at 50 days gestation (term is 67 days) of fetal guinea pigs whose amniotic fluid was drained on day 45 gestation. The study period spans the late canalicular-early saccular phases of guinea pig lung growth. Compared to littermate controls (n = 4), experimental fetuses (n = 5) have reduced lung:body weight ratio (2.81 +/- 0.16 versus 3.21 +/- 0.20 X 10(-2), p less than 0.01), indicating lung hypoplasia. Lung volume is significantly decreased in the experimental fetuses (1.17 +/- 0.15 versus 1.34 +/- 0.07 ml, p less than 0.05). The proportion of lung containing parenchyma (i.e. developing alveoli and alveolar ducts) is reduced following oligohydramnios (0.83 +/- 0.04 versus 0.90 +/- 0.02, p less than 0.025). The hypoplastic lungs contain fewer saccules (fetal "alveoli") (46 +/- 20 versus 69 +/- 23 X 10(6), p less than 0.1) and the surface area that would be available for gas exchange is decreased (698 +/- 234 versus 974 +/- 80 cm2, p less than 0.05). Lung volume and volume proportion of parenchyma are reduced in the experimental lung and therefore diminished parenchymal elastic tissue is anticipated. However, the total length of parenchymal elastic tissue in the experimental lungs is decreased to a surprising degree and is little more than half the length in control lungs (504 +/- 222 versus 974 +/- 70 m, p less than 0.0025). Such marked reduction in total length suggests that factors other than smaller lung size have contributed to the decrease of elastic tissue in the experimental group. In fact, elastic tissue length per unit volume is significantly reduced (509 +/- 189 versus 809 +/- 115 m/cm3, p less than 0.025) indicating an absolute decrease in parenchymal elastic tissue in the hypoplastic lungs.(ABSTRACT TRUNCATED AT 250 WORDS)

Amniotic Fluid↗
PubMed1985

Fetal lung hypoplasia associated with maternal smoking: a morphometric analysis.

Our recently reported animal (rat) model of maternal cigarette smoke exposure during pregnancy is characterized by fetal growth retardation and lung hypoplasia. We have further defined the fetal lungs using quantitative histologic techniques. Compared to controls, lung volume at term is reduced in the experimental animals (0.28 versus 0.33 ml, p less than 0.005). Saccules (fetal "alveoli") are reduced in number (3 X 10(6) versus 5.5 X 10(6), p less than 0.005) and increased in size (average saccular volume: 35 X 10(-9) versus 21 X 10(-9) ml, p less than 0.025). These changes in size and number are consequences of reduced formation of saccule partitions (septal crests) in the experimental lungs (volume density: 0.013 versus 0.018, p less than 0.025). Internal surface area is decreased in the hypoplastic lungs (161 versus 198 cm2, p less than 0.001). The total length of parenchymal elastic tissue is diminished (224 versus 354 M, p less than 0.05). In short the hypoplastic lungs contain fewer, larger saccules and the surface potentially available for gas exchange is reduced. These results show that maternal smoking in rats adversely modifies fetal lung growth. If these observations are applicable to humans, then reduced lung growth in children of smoking mothers may begin antenatally.

Animals↗
PubMed1985

Healing of ischemic colonic anastomoses in the rat: role of antibiotic preparation.

In this study we evaluated the relative effects of ischemia with and without antibiotic bowel preparation on colonic wound healing. Thirty-two Sprague-Dawley rats (185 to 300 gm) were divided into five study groups: Groups I and II (n = 14) had no colonic ischemia, half receiving antibiotic bowel preparation before colocolostomy. Groups III, IV, and V (n = 18) had colonic ischemia induced by division of the marginal artery and ligation of the arteries to the splenic flexure and pelvic colon, assuring that all blood supply to the left side of the colon was intramural. Enteral (neomycin and erythromycin) antibiotic preparation was given in group III, no antibiotics were given in group IV, and parenteral (clindamycin and gentamicin) preparation was given in group V. The mid-left side of the colon was transected and an everting anastomosis was constructed with continuous 6.0 silk sutures. All animals were killed on the seventh postoperative day. Anastomotic healing in unprepared, ischemic rat colon was severely impaired, with an 83% dehiscence rate. In the colon prepared with enteral antibiotics, no adverse effect of ischemia was found. No animal had dehiscence, proximal dilation of the colon, or intra-abdominal abscess. This study may have clinical relevance in patients with ischemic intestinal disorders.

Administration, Oral↗
PubMed1983

Experimental production of pulmonary hypoplasia following amniocentesis and oligohydramnios.

We have analyzed the impact of a single needle puncture of the fetal rat membranes on day 15 of gestation on growth and development at term (day 21). Untouched littermate fetuses served as controls. The procedure led to persistent oligohydramnios. The experimental fetuses weighed less, 94% of the weight of controls, P less than 0.01. Both lungs and liver weighed significantly less, 72% (P less than 0.01) and 89% (P less than 0.03) of controls respectively and there was no effect on brain weight. When the values were expressed as organ/body weight ratio only the lung/body weight ratio was significantly lower, 77% of controls, P less than 0.01. DNA per lung was less, 83%, as was lung DNA per gram of fetal weight, 89%, and the lung protein/DNA ratio was lower, 79%, indicating lung hypoplasia and hypotrophy (all three P values less than 0.01). There were no significant differences in either liver or brain biochemical analysis. We conclude that pulmonary hypoplasia associated with oligohydroamnios in the rat is a suitable animal model of the human condition.

Amniocentesis↗