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Biomedical subjects

T Gunn

Publications and source records attributed to T Gunn.

At least 19 recordsLinked to original sources
PubMed2001

Linkage of otopalatodigital syndrome type 2 (OPD2) to distal Xq28: evidence for allelism with OPD1.

Otopalatodigital syndrome type 1 (OPD1) is an X-linked semidominant condition characterized by malformations of the skeleton, auditory apparatus, and palate. Previous studies have established linkage to a 16-cM region of Xq27-q28. A proposed allelic variant of OPD1, termed "OPD2," is associated with a more severe, frequently lethal phenotype with visceral and brain anomalies in addition to skeletal, auditory, and palatal defects. We report linkage of the OPD2 phenotype to a 2-cM region of distal Xq28 in a Maori kindred, with a maximum multipoint LOD score of 3.31 between the markers DXS1073 and DXS1108. This provides support for allelism between OPD1 and OPD2 and reduces the size of the disease interval to 1.8-2.1 Mb. We also demonstrate that female carriers of this disorder exhibit skewed inactivation that segregates with the high-risk haplotype and may be inversely related to the severity with which they manifest features of the disorder.

Abnormalities, Multiple↗
PubMed2000

Biochemical and genetic studies of pigment-type switching.

Mutations that affect the balance between the synthesis of eumelanin and pheomelanin provide a powerful set of tools with which to understand general aspects of cell signaling. Previous work from our laboratory has demonstrated that pheomelanin synthesis is triggered by the ability of Agouti protein to inhibit signaling through the Melanocortin 1 receptor (Mc1r). In a bioassay based on the Xenopus Mc1r, Agouti protein has two effects, competitive inhibition of receptor occupancy by alpha-MSH and down-regulation of receptor signaling, which are mediated separately by domains in the amino- and carboxy-terminal regions of Agouti protein, respectively. Recently, we have used the genetics of pigmentation as an in vivo system to screen for and analyze other mutations in the Agouti-melanocortin pathway. The pigmentary effects of Agouti are suppressed by the previously existing coat-color mutations mahogany (mg), mahoganoid (md), and Umbrous (U). Double mutant studies, with animals deficient for the Mc1r or those which carry Ay, indicate that mg and md are genetically upstream of the Mc1r, and can suppress the effects of Ay on both pigmentation and body weight. Positional cloning has recently identified the gene mutated in mahogany as a single transmembrane-spanning protein whose ectodomain is orthologous to human Attractin (Atrn).

Agouti Signaling Protein↗
PubMed1997

Are Melnick-Needles syndrome and oto-palato-digital syndrome type II allelic? Observations in a four-generation kindred.

Melnick-Needles syndrome (MNS) is a female-limited skeletal dysplasia inherited in a X-linked dominant pattern. Males born to women with MNS may exhibit lethal multiple congenital anomalies, but recurrence of this phenotype within one family has not been reported. Males with oto-palato-digital syndrome type II (OPD II) also demonstrate a multiple congenital anomalies phenotype that includes skeletal dysplasia but the maternal phenotype includes only mild craniofacial anomalies. These two syndromes have been suggested as being allelic despite differences in the described maternal phenotypes. We present a four-generation kindred in which four males had a consistent multiple congenital anomalies phenotype. The females in this family have skeletal changes characteristic of MNS but have only mild craniofacial anomalies and also deafness attributable to ossicular deformity, traits more commonly found in OPD II. The expression of manifestations of MNS and OPD II in males and females in this kindred further suggest that these syndromes are allelic.

Abnormalities, Multiple↗
PubMed1997

Vertical transmission of hepatitis C virus in New Zealand.

AIMS: To investigate the transmission of hepatitis C virus from viraemic mothers to infants. METHODS: The study group comprised 54 hepatitis C ribonucleic acid (RNA) positive, human immunodeficiency virus (HIV) negative women attending antenatal clinic, their infants when born, 12 previous children and 44 children of 29 additional nonpregnant, viraemic women. During the study period there were 60 live births (1 set of twins, 5 sequential pregnancies). All infants were tested at birth for hepatitis C virus (HCV) RNA. Thirty infants were retested at 6 months or later. Breast milk from 30 mothers was tested for HCV RNA. The 56 other children were tested for antibody to HCV and HCV RNA. RESULTS: Of the 60 infants tested at birth, 30 failed to attend a 6 month or later followup, 2 infants were HCV viraemic by six months of age, 2 infants had one episode of possible HCV RNA positivity followed by loss of detectable HCV RNA and 26 have shown no evidence of HCV infection. Five of the 30 breast milk samples tested were positive for HCV RNA. Four older children of viraemic mothers were HCV RNA positive. CONCLUSIONS: In this study, 2 of 30 (6.6%) of infants born to HIV negative, HCV viraemic mothers acquired HCV infection. Breast milk remains a possible contributory source of infant HCV infection. Management of babies born to HCV viraemic mothers should include retesting of baby for HCV RNA at 3 to 6 months of age.

Adult↗
PubMed1987

A combination of hepatitis B vaccine and immunoglobulin does not protect all infants born to hepatitis B e antigen positive mothers.

In 42 infants of hepatitis B e antigen positive carrier mothers a randomised study of a low dose (5 micrograms) hepatitis B vaccine regimen starting within 24 hours of birth with or without hepatitis B immunoglobulin (0.25 ml/kg) showed that in the vaccine group 72% were antibody positive at the age of one year and in the vaccine plus immunoglobulin group 81%. In the vaccine group four of 18 infants were not protected and in those infants receiving vaccine plus immunoglobulin three of 21 were HBsAg carriers by 12 months of age. Hepatitis B vaccine either with or without concomitant HBIg did not protect all babies born of HBeAg positive mothers, from developing the HBsAg carrier status. Thus for full protection of all infants a more vigorous immunisation programme will be necessary.

Carrier State↗
PubMed1985

Passive immunoprophylaxis of hepatitis B virus infections in newborn infants.

Newborn infants of mothers who were chronic carriers of hepatitis Bs antigen (HBsAg) were randomly allocated to be treated or not treated with hyperimmune hepatitis B immunoglobulin (HBIg) at birth and six weeks and were then followed up to one year with sequential blood tests. Ninety percent of all untreated infants born of mothers positive for both HBsAg and hepatitis Be antigen became chronic carriers of HBsAg at one year. In contrast only 9% of infants treated with HBIg became HBsAg positive. Mothers who were HBsAg positive but hepatitis Be antigen negative only uncommonly infected their infants, with 6% being HBsAg positive at one year. Nearly all infections were in Pacific Islanders, Maoris or Asians. It is recommended that antenatal testing of these groups most at risk for hepatitis B virus spread, be initiated, followed by passive immunoprophylaxis with HBIg of infants born of HBsAg, HBeAg positive mothers.

Carrier State↗
PubMed1984

Neonatal seizures: aetiology and outcome.

Neonatal seizures occurred in 23 infants, a rate of 2.33 per 1000, 1978-81. In two infants these were due to congenital central nervous system malformation and in two infants hypocalcaemia. Hypoxic encephalopathy was the cause of the seizures in 19 infants, two of whom also suffered perinatal trauma. Pacific Island infants were overly represented in this group. The gestational age was 41, SD 1.8 weeks, birth weight 3140, SD 720 g; nine infants were 41 weeks or older although nine had unsure data and nine were small for gestational age. Despite vigorous resuscitation at birth, careful metabolic monitoring in the neonatal period and treatment with anti-convulsant medication, at follow-up evaluation 12 (67%) of the infants with hypoxic encephalopathy died or had neurologic sequelae.

Birth Injuries↗
PubMed1984

Perinatal mortality at a level 2 obstetric hospital: problems after 32 weeks gestation.

The aim of this study was to find ways to reduce perinatal mortality. At St Helens Hospital there were 9876 births in the four year period 1978-81 and 93 perinatal deaths occurred, a perinatal mortality rate of 9.42 per 1000, stillbirths 6.58 and early neonatal deaths 2.84. Since 1971 the perinatal rate has been reduced by 29%. Perinatal anoxia was the major cause of death affecting 56 (5.67 per 1000). Only one infant each died of obstetric trauma, and respiratory distress syndrome, 0.1 per 1000. Infection affected four (0.4 per 1000) and lethal congenital abnormalities 24 (2.43 per 1000). Potentially medical avoidable factors were found to have occurred in 31% of the mothers and patient avoidable factors in 6% of mainly late or unbooked mothers. Unsure or incorrect dates in many mothers increased the difficulties in the recognition of infants with intrauterine growth retardation who are at high risk of hypoxia.

Cerebral Hemorrhage↗
PubMed1981

The effect of varying protein quality and energy intake on the nitrogen metabolism of parenterally fed very low birthweight (less than 1600 g) infants.

Net nitrogen retention (NNR) and rates of whole-body protein turnover (Q), synthesis, and breakdown (B) were measured in 24 intravenously fed premature infants, birthweight less than 1600 g, at the end of the first week of life. Four regimes were used: Amigenglucose +/- Intralipid; Vamin-glucose +/- Intralipid. Mean protein intake was 2.7 g/kg/day. Mean energy intakes were 68 to 98 kcal/kg/day. Vamin was a better protein source (p less than 0.01), evidence by a higher NNR; 72 +/- 2%, cf. 56 +/- 4% at high-energy intakes. The high-energy intake also improved (p less than 0.01) protein retention (NNR); 64 cf. 50%. Infants receiving 2.9 g of Vamin (394 mg N)/ kg/day and 85 kcal/kg/day of nonprotein intake retained nitrogen at intrauterine rates (282 +/- 7 mg/kg/day). Diet had no effect on Q, synthesis, or B. However, the protein source had a significant effect (p less than 0.01) on the fraction of N-flux coming from protein breakdown (B/Q); 71.7% for Vamin, cf. 77.1% for Amigen. Similarly, energy intake had a significant effect (p less than 0.01) on the fraction N-flux utilized for protein synthesis (S/Q); 91.3% high energy cf. 87.0% low energy. These results suggest that an increased energy intake improved N-retention by enhancing amino acid reutilization for protein synthesis, whereas a higher quality protein improved N-retention by limiting protein breakdown..3% high energy cf. 87.0% low energy. These results suggest that an increased energy intake improved N-retention by enhancing amino acid reutilization for protein synthesis, whereas a higher quality protein improved N-retention by limiting protein breakdown..3% high energy cf. 87.0% low energy. These results suggest that an increased energy intake improved N-retention by enhancing amino acid reutilization for protein synthesis, whereas a higher quality protein improved N-retention by limiting protein breakdown.

Diet↗
PubMed1981

Depressed T cells following neonatal steroid treatment.

Fourty-four patients received two doses of 12.5 mg/kg of hydrocortisone or placebo on the first day of life in attempted therapy for respiratory distress syndrome. Follow-up studies were performed on survivors at 5 years of age in ten steroid-treated and seven placebo-treated respiratory distress syndrome subjects. There were no significant differences in growth, intelligence tests, or neurologic examinations in the patients assessed. Abnormal EEGs are present in both groups. Immunologic tests showed no differences in lymphocyte counts, immunoglobulin levels, diphtheria and tetanus antibody titers, or complement components. Diminished percentages of T lymphocytes were found in steroid patients (53%) compared to control subjects (69%). There were also increased percentages of lymphocytes with C3 receptors in steroid patients (20.1%) compared to control patients (13.8%). Episodes of otitis and/or pneumonia were documented in eight of 11 steroid-treated patients between the ages of 1 and 5 years, compared to two of seven patients in the placebo group in the same time period. It is concluded that large doses of steroids on the first day of life may induce lasting immunologic abnormalities and may predispose to an increased incidence of infections.

Anthropometry↗
PubMed1981

[Larval morphology and biology of Gongylonema soricis Fain, 1955 (author's transl)].

The spirurid nematode Gongylonema soricis Fain, 1955, the parasite of shrews from Zaïre and Ruanda Urundi has been identified in shrews from Togo. Its infective larva has been obtained experimentally from Periplaneta orientalis as intermediate host. The larval characteristics of G. soricis link it to the G. brevispiculum type, one of the four larval morphological types which have been classified in the genus Gongylonema.

Animals↗
PubMed1978

Effectiveness of neonatal transport.

The condition of 259 infants transferred to the neonatal intensive care unit (NICU) of the Montreal Children's Hospital from Oct. 1, 1974 to Mar. 31, 1975 was evaluated. Their transport was provided by personnel and equipment from the Montreal Children's Hospital. When the transport team arrived at the referring hospital hypothermia (temperature of less than 36 degrees C) was present in 25.2% of the 163 infants for whom complete temperature measurements were available. Most (77.3%) of the infants were warmed during transport and only 3.1% arrived at the NICU with a temperature of less than 35 degrees C. The mortality was significantly higher in babies of all birth weight groups whose core temperature had been below the optimal temperature for survival (36 to 37 degrees C). It appears that the use of appropriate equipment and trained personnel can reduce the incidence of hypothermia and therefore the mortality in infants requiring transfer.

Body Temperature↗
PubMed1978

Peripheral total parenteral nutrition for premature infants with the respiratory distress syndrome: a controlled study.

In 40 premature infants, in whom severe respiratory distress precluded oral feeding, peripheral total parenteral nutrition consisting of casein hydrosylate, dextrose, and soybean emulsion was compared to nutrition with dextrose and electrolytes. The TPN group received more calories, and the total serum protein in them increased significantly. Metabolic complications did not occur. Transient thrombocytosis occurred in six infants who received TPN and eosinophilia occurred in nine. The case fatality rate in the TPN group (three of 20) was not significantly less than in the glucose group (six of 20). The differences suggested that infants who weigh less than 1,500 gm may receive the greater benefit from TPN.

Blood Proteins↗