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Biomedical subjects

J F Murphy

Publications and source records attributed to J F Murphy.

At least 19 recordsLinked to original sources

The development of enzyme-linked immunosorbent assays (ELISA) for the catecholamines adrenalin and noradrenalin.

Monoclonal antibodies have been raised against adrenalin and noradrenalin and used as the basis of enzyme-linked immunosorbent assays (ELISA) to detect and estimate the concentrations of these catecholamines. Inhibition assays are described, with sensitive quantification in the range from 1 mg/ml to 100 pg/ml. Cross-reactivity assays reveal that neither assay is subject to interference by catecholamine metabolites at concentrations less than 100 ng/ml and 1 micrograms/ml respectively. Isolation and quantification of both catecholamines from clinical samples is discussed and the potential application of these ELISAs in a clinical setting is proposed.

Animals

Radiographic screening at four months of infants at risk for congenital hip dislocation.

We report on a radiographic screening programme at four months of age for infants who were clinically normal at neonatal examination but were considered to be 'at risk' for congenital dislocation of the hip because of their family history, breech presentation, or a persistent click. From a total population of 13,662 live births over a two-year period, 357 (2.6%) infants at risk were identified. Of these 46 had abnormal radiographs (six subluxations, 40 acetabular dysplasia). In 12 infants treatment resulted in a normal hip; 34 required no treatment but were followed up until their radiographs were normal and walking had begun. Of the 311 infants with normal radiographs, 256 (82%) were examined after 15 months of age; none had any detectable abnormality. We suggest that radiography of the hip at four months is a valuable adjunct to neonatal screening for infants at increased risk of congenital dislocation of the hip.

Acetabulum

En bloc radical vulvectomy and lymphadenectomy with modifications of separate groin incisions.

A new modification of radical vulvectomy and lymphadenectomy through separate groin incisions involves dissection of the intervening skin bridge and allows an en bloc dissection. The results in 26 women treated with this technique are compared with those of seven treated with separate incisions without an en bloc dissection. All 33 women had squamous carcinoma of the vulva and were treated between 1985-1989. The incidence of advanced disease was high, with nodal metastases present in 52% of cases. Dissection of the tissue beneath the skin bridge did not alter the morbidity of the procedure in terms of the incidence of wound infection, number of units of blood transfused, or duration of hospitalization. The only case of an isolated recurrence in the skin bridge occurred in a woman who did not have an en bloc dissection, although there was no significant difference in the overall local recurrence rate between the groups. Further evaluation with larger numbers is required, but we suggest that an en bloc dissection using separate incisions may reduce the risk of isolated recurrence in the skin bridge, particularly in patients with advanced disease.

Adult

Outpatient loop diathermy conization as an alternative to inpatient knife conization of the cervix.

A knife cone biopsy of the cervix is usually performed as an inpatient procedure under general anesthesia and is associated with significant morbidity. Loop diathermy conization was performed under local anesthesia on colposcopy outpatients as an alternative to knife conization. In 33 consecutive patients studied the procedure was well tolerated, there were no operative complications, and a satisfactory specimen for histologic examination was obtained in every case. One case of unsuspected invasive cancer and two of suspected microinvasive cancer were diagnosed. The diagnosis of cervical precancer was made in 24 (73%) of the cases. The introduction of outpatient loop diathermy conization of the cervix instead of knife conization would decrease hospitalization costs, avoid the need for general anesthesia and potentially reduce short-term patient morbidity.

Adult

VPg-mediated aggregation of potyviral RNA.

RNA prepared from the potyvirus tobacco vein mottling virus contained aggregates of the 9.5 kb genomic RNA with electrophoretic mobilities corresponding to 20 and 41 kb species. Similar aggregates were present in preparations of the RNAs of two other potyviruses. Aggregation occurred during or after purification of the RNA by sucrose gradient centrifugation and alcohol precipitation and was dependent upon the presence of a protein apparently bound covalently to a region at or near the 5' terminus of the viral RNA. This protein is probably the VPg. The RNAs of tobacco mosaic virus and cowpea mosaic virus did not form aggregates when isolated from purified virus by similar procedures.

Electrophoresis, Agar Gel

A tyrosine residue in the small nuclear inclusion protein of tobacco vein mottling virus links the VPg to the viral RNA.

The identity of the amino acid residue that links the VPg of the potyvirus tobacco vein mottling virus (TVMV) to the viral RNA was determined. 32P-labeled TVMV RNA was digested with RNase A and micrococcal nuclease. The resulting 32P-labeled VPg was isolated and partially hydrolyzed with 6 N HCl at 110 degrees C for 2 h. Analysis by thin-layer electrophoresis revealed the presence of [32P]phosphotyrosine but not [32P]phosphoserine or [32P]phosphothreonine. Another preparation of TVMV RNA was treated with endoproteinase Lys-C, and the resulting peptide-RNA was purified by sodium dodecyl sulfate-sucrose gradient centrifugation. The sequence of the N-terminal 15 amino acid residues of the peptide, when compared with the RNA-derived amino acid sequence of the TVMV polyprotein, demonstrated that the peptide occurs in the small nuclear inclusion protein. These data suggest that Tyr-1860 of the polyprotein is the amino acid residue that links the TVMV VPg to the viral RNA.

Amino Acid Sequence

Clinico-pathological findings in non-immune hydrops fetalis.

Non-immune hydrops fetalis is becoming a relatively more important cause of hydrops as the incidence of rhesus-related hydrops falls. We describe a series of 33 cases, occurring over a 7 year period covering most of the 1980's. We found a very wide range of aetiological factors, but cardiac conditions, both structural and dysrhythmic, formed the largest subgroup (12 cases, 36%). Seven cases (22%) remained idiopathic. Prognosis was very poor, with only 4 infants surviving. Outcome was best in the cases due to intra-uterine supraventricular tachycardia. Nineteen cases were detected antenatally, but except in the cases of fetal tachyarrhythmias, this had little effect on outcome.

Female

A clinical review of cervicography.

A new investigative modality, cervicography, has been advocated for cervical screening. In the first 51 patients referred for colposcopy because of an abnormal cervicogram, none had invasive cancer and 75% had preinvasive cancer. The cervicogram appears superior to cytology but inferior to colposcopy in the detection of cervical pathology. Based on the available evidence, however, cervicography cannot be recommended for universal screening. It may have a role in the follow-up of patients with a mildly abnormal cervical smear, but the optimum management remains early referral for colposcopy.

Adult

The VPg of tobacco etch virus RNA is the 49-kDa proteinase or the N-terminal 24-kDa part of the proteinase.

Preparations of tobacco etch virus (TEV) RNA which were purified by sucrose gradient centrifugation, digested with RNase, and analyzed by SDS-polyacrylamide gel electrophoresis contained proteins of 49, 32, and 24 kDa. The 49- and 24-kDa proteins reacted with polyclonal antiserum to the TEV 49-kDa proteinase while the 32-kDa protein reacted with anti-TEV serum. Further purification of the RNA by centrifugation through CsCl removed the coat protein (32 kDa), but not the 49- and 24-kDa proteins. The 49- and 24-kDa proteins did not migrate into a polyacrylamdie gel when the RNA was not digested with RNase. These results indicate that the VPg of TEV is either the 49-kDa proteinase or the 24 kDa that represents the amino-terminal half thereof.

Centrifugation, Density Gradient

Cytological screening history of patients with early invasive cervical cancer.

The value of population screening for cervical cancer has recently been questioned. The purpose of this study was to examine the cytological screening history in 100 consecutive patients undergoing Wertheim's hysterectomy for early invasive cervical cancer. Twenty three per cent of the patients were never screened; the screening history was unavailable in 11%; the patient was referred appropriately in 21%; there was a delay in referral for gynaecological assessment in 21%; the patient's previous cervical smear before referral was normal in 24%. If population screening in Ireland is to have an impact on mortality from cervical cancer, the results of this study indicate that greater attention needs to be given not only to extending the number of women screened, but also to increasing the frequency of screening and to improving the clinical response to an abnormal smear.

Adenocarcinoma

Distant metastases following surgical treatment of cervical carcinoma.

Fifty patients with early carcinoma of the cervix were treated by radical hysterectomy and pelvic lymphadenectomy. Twelve patients (24%) had positive nodes and received adjuvant pelvic radiotherapy. The mean duration of follow-up was seven years and all patients had at least four years follow-up. Five patients died from recurrence; four from isolated distant metastases and one from a pelvic side wall recurrence. The disease-free interval for patients with distant metastases was six months to two years and the metastases were to lung and bone.

Adult

Epidural versus general anaesthesia for elective caesarean section. Effect on Apgar score and acid-base status of the newborn.

Elective Caesarean section deliveries over a 5-year period were studied to compare the effect of epidural block with general anaesthesia on the condition of the infant at birth. The Apgar score and umbilical arterial acid-base status were used as determinants of the latter. Epidural block was used in 139 (22.8%) mothers while 471 (77.2%) were performed under general anaesthesia. No babies in the epidural group were severely depressed (Apgar less than 4), compared with 6.2% in the general anaesthesia group. Only 4.3% of the epidural sections were moderately depressed (Apgar 4-6), compared with 15.4% of the others. These differences remained highly significant when infants of less than 2500 g were excluded, and when matched groups were compared. Mean umbilical arterial pH was similar within the two groups (pH 7.28), and was not consistent with asphyxia in almost 90% of the depressed infants. The findings suggest that general anaesthesia, rather than asphyxia or aortocaval compression, is responsible for most of the depressed infants born by elective Caesarean section. This may involve over 20% of babies delivered in this manner, so greater use of epidural block for elective Caesarean section is recommended. Further investigations are required to improve results with general anaesthesia.

Acid-Base Equilibrium

Catch up growth in preterm infants.

Seventy-one surviving infants were followed up from birth to 24 weeks of postnatal age. Their mean gestational age was 32 weeks with a range of 26-36 weeks and a standard deviation of 2.1 weeks. Their mean birth weight was 1,805 kg with a range of 0.675-2.5 kg and a standard deviation of 0.408 kg. Their weights, lengths and head circumferences were measured at birth, 6, 12 and 24 weeks. Curves for the mean weight, length and head circumference were produced and superimposed on the available intrauterine and extrauterine growth charts. The growth curves of the preterm infants did not show the flattening noted in the intrauterine curves towards term. The curve of the mean weight of the preterm infants started at the 50th centile for Gairdner & Pearson (1971) at birth to drop below that shortly after birth. At 40 weeks of postconceptional age the mean weight curve of preterm infants crossed the 50th centile and continued above it to reach the 90th centile at 60 weeks. The curves of mean length and head circumference started below the 50th centile at birth and crossed it at 40 weeks and continued above it to approach the 90th centile at 60 weeks. Growth velocity was calculated as a relative gradient using the straight line equation (y = a + bx), where y is the weight, length or head circumference, and x is the independent variable and here it is the group mean of the parameter at the corresponding ages. Catch up growth is taken as a relative gradient significantly greater than one. The first 24 weeks of postnatal life are defined as a period of catch up growth with the first 8 weeks as an interval of maximum head velocity.

Age Factors

Plasma zinc concentration and catch up growth in preterm infants.

Changes in plasma zinc concentration during the period of catch up growth were examined in 44 preterm infants. Blood samples were collected at birth, 6, 12 and 24 weeks. Plasma zinc concentration showed a mean of 13.6 mumol/l at birth and dropped to 9.8 mumol/l at 6 weeks and rose to 11.3 and 15.4 mumol/l at 12 and 24 weeks respectively. Plasma zinc concentrations showed significant correlation with weight velocity at 12 weeks. Male infants had significantly lower plasma zinc concentrations than females at 12 weeks. Infants of gestational age more than 32 weeks had lower plasma zinc concentrations at 12 and 24 weeks than those of earlier gestations. At the same time males were growing faster than females and also infants of gestational ages more than 32 weeks were growing faster than those born at earlier gestations. These observations, together with the finding that the decline in zinc occurred during the phase of rapid growth, suggest that growth is the predominant modulator of plasma zinc concentration.

Age Factors

Neonatal parenteral nutrition with a fat emulsion containing medium chain triglycerides.

Fifty-one newborn infants requiring parenteral nutrition were randomly assigned to receive a 50% medium chain triglyceride/50% long chain triglyceride lipid emulsion or the conventional 100% long chain triglyceride emulsion. Fat was administered daily for 20 hours, to a maximum of 3 g/kg/day. Plasma triglycerides, cholesterol, free fatty acids, ketones, glucose and capillary blood gases were monitored daily up to the sixth day of fat infusion. There were no significant differences in mean plasma triglycerides and free fatty acids between the two groups. No cases of hyperketonaemia were detected in the infants studied. Hyperglycaemic episodes were detected with similar frequency in both groups. The group who received the emulsion containing medium chain triglycerides had significantly lower mean plasma cholesterol values during the study. After 6 days of intravenous fat administration mean plasma cholesterol was more than 100% higher in the group which received the conventional emulsion. Differences in cholesterol content between the emulsions and a cholesterol lowering effect of medium chain triglycerides are possible explanations for these findings.

Cholesterol

Assessment of adrenocortical activity in term newborn infants using salivary cortisol determinations.

Salivary cortisol concentrations were collected every 2 hours over a 24-hour period in eight healthy 2-day-old term neonates. Two maxima in cortisol output were noted, neither being related to the time of day or time since birth. Salivary cortisol concentrations ranged from 2.5 to 57.4 nmol/L (0.09 to 2.08 micrograms/dL), and throughout the 24 hours showed considerable variation (21% to 42%) not related to the state of arousal. The validity of the method was confirmed by collecting matched plasma and saliva samples from another group of 36 neonates. The correlation between plasma and saliva cortisol was r = 0.83. We suggest that salivary cortisol is a useful, noninvasive method of studying adrenocortical status in the newborn infant.

Adrenal Cortex