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Biomedical subjects

H Nichol

Publications and source records attributed to H Nichol.

16 recordsLinked to original sources
PubMed1999

Secreted ferritin subunits are of two kinds in insects molecular cloning of cDNAs encoding two major subunits of secreted ferritin from Calpodes ethlius.

In insects, holoferritin is easily visible in the vacuolar system of tissues that filter the hemolymph and, at least in Lepidoptera, is abundant in the hemolymph. Sequences reported for insect secreted ferritins from Lepidoptera and Diptera have high sequence diversity. We examined the nature of this diversity for the first time by analyzing sequences of cDNAs encoding two ferritin subunits from one species, Calpodes ethlius (Lepidoptera, Hesperiidae). We found that insect secreted ferritin subunits are of two types with little resemblance to each other. Ferritin was isolated from iron loaded hemolymph of C. ethlius fifth instar larvae by differential centrifugation. The N-terminal amino acid sequences for the nonglycosylated subunit with Mr 24,000 (S) and the largest glycosylated subunit with Mr 31,000 (G) were determined. The N-termini of the two subunits were different and were used to construct degenerate PCR primers. The same cDNA products were amplified from cDNA libraries from the midgut which secretes holoferritin and from the fat body which secretes iron-poor apoferritin. The G subunit most closely resembles the glycosylated ferritin subunit from Manduca sexta and the S subunit resembles the Drosophila small subunit. The S and G subunits from Calpodes were dissimilar and distinct from the cytosolic ferritins of vertebrates and invertebrates. Additional sequences were obtained by 5' and 3' RACE from separate fat body and midgut RACE libraries. cDNAs encoding both subunits had a consensus iron responsive element (IRE) in a conserved cap-distal location of their 5' UTR. An integrin-binding RGD motif found in the G subunit and conserved in Manduca may facilitate iron uptake through a calreticulin (mobilferrin)/integrin pathway. Calpodes and other insect ferritins have conserved cysteine residues to which fatty acids can be linked. Dynamic acylation of ferritin may slow but not prevent its passage out of the ER.

Amino Acid Sequence↗
PubMed1993

Interdisciplinary approach to functional voice disorders: the psychiatrist's role.

A review is given of the experience obtained over 6 years of having a psychiatric consultant available as part of the staff of the Voice Clinic, to which more than a thousand patients have been referred. The presenting features in a case that should alert the otolaryngologist to the need for psychiatric consultation and possible treatment are noted. Suggestions are made as to how to prepare the patient for the referral to a psychiatrist with the appropriate interests and willingness to collaborate closely with the otolaryngologist and the speech pathologist.

Humans↗
PubMed1991

The visualization of apoferritin in the secretory pathway of vertebrate liver cells.

Electron microscopy has shown that normal mouse liver cells contain abundant cytosolic and lysosomal holoferritin but none in cisternae of the rough endoplasmic reticulum (RER). This does not mean that ferritin is absent from the secretory pathway, since the low contrast of apoferritin and ferritin containing little iron makes it difficult to resolve using standard transmission electron microscopy. We hypothesized that treatment of permeabilized cells and cell fractions with iron should make apoferritin visible by converting it to holoferritin. The iron treatment caused particles resembling the cores of holoferritin to appear in RER and in RER microsomes from mouse liver. We conclude that ferritin occurs in the endoplasmic reticulum and could be secreted, allowing the liver to be a source of serum ferritin.

Animals↗
PubMed1987

Impaired interns and residents.

In 1981 a study was undertaken to determine intern and resident psychological well-being and identify those house staff who were psychologically impaired. Fourteen percent of house staff were found to be impaired. Single females and house staff who were chronically fatigued or socially isolated were at highest risk for impairment. Impairment arose out of the interaction between sleep and social deprivation and individual vulnerability. Minor tranquilizers, but not alcohol, were used as a coping response to impairment.

British Columbia↗
PubMed1986

Diagnostic criteria in functional dysphonia.

One thousand consecutive patients seen in a multidisciplinary voice clinic are reviewed. The incidence and relative severity of diagnostic features in each of five assessment areas are calculated and compared. The five areas include: 1. history, 2. laryngoscopic examination, 3. perceptual-acoustic assessment, 4. voice related musculoskeletal, and 5. psychological evaluations. Feature prevalence is presented for patients we have classified as having muscular tension dysphonia, which can be primary, or associated with vocal nodules, chronic laryngitis, or polypoidal degeneration; or as having a psychogenic "functional" dysphonia. Following review of the data, we present a suggested list of diagnostic criteria that should be present before using a specific diagnostic label. These criteria have been further broken down into those that will be present to make a diagnosis, and those that may be present.

Adult↗
PubMed1983

The voice clinic: an interdisciplinary approach.

The University of British Columbia Voice Clinic provides care to patients with various types of voice disorder, and the effectiveness of therapy is enhanced by an interdisciplinary approach. The Voice Clinic team includes an otolaryngologist, speech pathologist, psychiatrist, and singing teacher consultant. This paper particularly highlights the interactions between the speech pathologist and psychiatrist in their therapy programs for voice disordered patients.

British Columbia↗
PubMed1983

Muscular tension dysphonia.

Muscular tension dysphonia (MTD) is a condition commonly seen in young and middle aged females. It is manifest by excess tension in the paralaryngeal and suprahyoid muscles, an open posterior glottic chink, larynx rise, and frequently mucosal changes on the vocal cords. These mucosal changes are usually fleshy vocal nodules. About 8% of vocal nodules are found in patients not exhibiting features of MTD. The two types of vocal nodules require different therapeutic approaches. One hundred patients out of 500 seen consecutively at the Voice Clinic at the University of British Columbia exhibited the features of MTD. These patients are discussed and an etiology hypothesis is presented.

Adolescent↗
PubMed1980

Quantitation of doxapram in blood, plasma and urine.

Methods for the quantitation of doxapram in blood, plasma and urine have been developed. Following extraction, gas-liquid chromatography was used to separate doxapram from basic metabolites. Doxapram was detected by mass spectrometry for blood and plasma assays, and by flame ionisation for urine assays. The limit of reliable quantitation in blood and plasma was 10 ng and in urine 500 ng, the coefficients of variation being 6.37%, 1.72% and 2.31% respectively. To illustrate the clinical applicability of the assay methods, plasma, blood and urine levels were monitored in a premature newborn following an intravenous infusion of doxapram.

Apnea↗
PubMed1979

Incidence of psychiatric treatment of adolescents.

The characteristics of adolescents aged 15-19 years who received psychiatric treatment for the first time in British Columbia in 1966 are considered. Females predominated substantially over males, as did those living in urban areas over those in rural ones. Somatic, psychological, behavioural and suicidal presenting problems were commoner in females, with delinquent and academic ones being more frequent in males. Depression, psychoneurosis and personality disorders were commoner in females. Medication was used in conjunction with psychotherapy more frequently in females. Long-term psychotherapy (more than 16 visits to a psychiatric facility) was employed in only 3% of females and 2% of males. Psychiatrists provided the greatest amount of care given. The hypothesis that females from rural areas living in the city constitute a vulnerable group of individuals more likely than their adolescent peers to seek psychiatric care requires evaluation in a further study.

Adolescent↗
PubMed1977

A developmental hierarchy of dyadic relationships.

With the work of Mahler, Bowlby and others it has been increasingly recognized in recent years that there is a sequential progression in the nature of the first dyadic relationship which forms the basis for the type and quality of subsequent interpersonal transactions. Four levels of development of dyadic relationship may be recognized. To begin with the infant is in a state of not recognizing the existence of the other individual - the autistic phase. At the toddler stage there is awareness of a separateness of physical attributes between the child and the significant other, but the persistence of the symbiotic belief that there is substantial co-extension of mental processes between the two. With further separation and individuation in the pre-school and early school-aged child, a period of magical thinking prevails for varying durations in the child, in which there is an attempt made to retain an omnipotent control of the thinking of the significant other by the mechanism of projection of thought. In the mid-elementary school-aged child the decentering process emphasized by Piaget, together with the emerging capacity for making allowance for the context within which events occur, leads to the dyadic relationship being seen by the child as being mediated through the transactions of two autonomous mental apparatuses. Dependent upon the quality of the first dyadic relationships, the nature of the communication which occurs in them, of traumatic psychological events and of the integrity of the integrated forces of personality formation, residues of earlier modes of perceiving the dyadic relationship may be encountered. Examples of these in adolescent and adult patients are given. The recognition of the possibility of shifts in the perception of the levels of the dyadic relationship is of importance in the conduct of individual pschotherapy, as the therapist can then deal more realistically with such topics as the establishment of goals, the management of the modes and quality of communication, as well as of transference and counter-transference relationships. This is particularly true of the treatment of patients with poorly integrated personalities. The fluctuations referred to are seen most dramatically with some schizophrenic patients.

Adult↗