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Biomedical subjects

K MacKenzie

Publications and source records attributed to K MacKenzie.

At least 19 recordsLinked to original sources
PubMed1996

The use of the CO2 laser for airway maintenance in obstructive supraglottic carcinoma.

CO2 laser 'debulking' of obstructive supraglottic tumours is an alternative to tracheostomy to restore the compromised airway. Two patients have successfully undergone radiation therapy after laser vaporization of their large supraglottic tumours, and did not require tracheostomy. This technique is relatively simple, avoids the morbidity of tracheostomy and facilitates early irradiation.

Aged↗
PubMed1995

Discrimination between Gyrodactylus salaris, G. derjavini and G. truttae (Platyhelminthes: Monogenea) using restriction fragment length polymorphisms and an oligonucleotide probe within the small subunit ribosomal RNA gene.

The small subunit ribosomal RNA (srRNA) gene was amplified from Gyrodactylus salaris using the polymerase chain reaction (PCR), cloned, and the complete gene sequence of 1966 bp determined. The V4 region of the srRNA gene was identified and amplified from single specimens of G. salaris, G. derjavini and G. truttae. Comparison of the V4 sequences from these three species revealed sequence differences from which restriction fragment length polymorphisms (RFLPs) were predicted and an oligonucleotide probe (GsV4) specific to G. salaris designed. Digestion of the amplified V4 region of the srRNA gene with Hae III and either Alw I, BstY I, Dde I or Mbo I provided a means of discriminating between G. salaris, G. derjavini and G. truttae. The GsV4 probe was used to detect the srRNA gene from G. salaris in Southern and dot blots of the amplified V4 region.

Animals↗
PubMed1995

The effect of recurrent tonsillitis and tonsillectomy on growth in childhood.

The aim of this study was to determine if children with recurrent tonsillitis are smaller than expected before tonsillectomy and if they have an altered height or weight gain 1 year post-operatively. All (204) children attending the hospital for tonsillectomy with or without adenoidectomy had their height and weight measured pre-operatively and 1 year after operation. The results of 2204 children in local schools were used as a control population. Analysis was by comparison of each population with the Tanner charts. This study suggests that our population of children listed for tonsillectomy were not lighter or smaller than expected before operation but that one year after tonsillectomy, there was an increase in their weight gain. The height gain was no different than expected after operation. Overweight seems to be a medium term complication of tonsillectomy. It may be necessary to redefine the indications for tonsillectomy in children who are already obese.

Body Constitution↗
PubMed1993

Histiocytosis: an unusual cause of dysphagia, hoarseness and stridor.

We present a patient with established histiocytosis who developed dysphagia, retching, regurgitation, hoarseness and stridor. These symptoms were managed with carbon dioxide laser vaporization, electively on three occasions, and once as an urgent procedure, while awaiting radiotherapy, to control her airway. Histiocytosis is a rare cause of a number of otolaryngological syndromes, but there has been no previous record of this disease causing laryngopharyngeal symptoms. This paper discusses the classification of histiocytosis, and describes our management of this rare and intriguing case.

Deglutition Disorders↗
PubMed1993

Elevated levels of the p53 tumour suppressor protein in the basal layer of recurrent laryngeal papillomas.

Using immunocytochemical techniques, recurrent laryngeal papillomas from six adult patients were studied. The p53 tumour suppressor gene protein was detected in the basal epithelial cells in papillomas from all six patients. None was detected in normal epithelium. Elevated levels of p53 protein are usually indicative of its inactivation either by point mutation or by complexing with tumour virus proteins.

Adult↗
PubMed1992

The acceptability of secondary tracheo-oesophageal fistula creation in long standing laryngectomees.

The use of a tracheo-oesophageal voice prosthesis was introduced to the Glasgow Royal Infirmary Otolaryngology, Head and Neck Surgery unit in 1986. Although it was the authors' impression that most total laryngectomees since then had been offered this method of voice restoration, it was thought that long standing laryngectomees were seldom offered tracheo-oesophageal fistula (TOF) speech. Therefore all 58 total laryngectomees currently attending the combined head and neck surgery/radiotherapy clinic were assessed. Thirty-two had a tracheo-oesophageal fistula with voice prosthesis. All of these patients had undergone their total laryngectomy since 1986 and 83 per cent had achieved TOF speech. The remaining 26 patients (who mostly had their laryngectomy before 1986) had not been offered TOF speech. An outpatient consultation was arranged for these patients and 63 per cent of those offered, accepted TOF creation and a voice prosthesis. When compared to those who refused, it was found that good oesophageal speech, age or interval since laryngectomy were not good predictors of likely refusal. This study indicates that all fit long standing laryngectomees should be offered secondary TOF creation.

Adult↗
PubMed1992

Effects of cyclosporin A on the morphology and tegumentary ultrastructure of Hymenolepis microstoma in vivo.

Cyclosporin A (CsA) induced significant changes in parasite morphology when administered to mice infected with Hymenolepis microstoma. Gross morphological damage consisted of proglottis swelling and the formation of protuberances from the worm surface, visible with a low-power dissecting microscope, occurring most frequently in the posterior third of the strobila. Gross morphology and ultrastructure were examined further using scanning and transmission electron microscopy. Swollen proglottides exhibited areas covered in small pits and fissures (diameter approximately 1-2 microns) but it was not possible to establish the significance of this damage. The brush-border and distal cytoplasm appeared largely intact although some evidence of swelling of the basal membrane invaginations and possible fluid accumulation was seen in drug-treated TEM sections. The apparent oedematous condition of many of the proglottides from drug-treated mice may indicate that CsA treatment mediates permeability changes in the worm surface membrane but the mechanisms by which this may occur remain to be elucidated. The effects of CsA on the morphology of H. microstoma correlate with the previously described anthelmintic activity of the drug against this parasite where CsA treatment dramatically reduces worm growth, retards migration into the bile duct and limits parasite survival.

Animals↗
PubMed1992

Both myeloproliferative disease and leukemia are induced by transplantation of bone marrow cells expressing v-myc.

An in vivo system has been established to investigate v-myc-induced hematopoietic neoplasia in mice. A Moloney murine leukemia virus (Mo-MLV)-derived recombinant retrovirus containing v-myc was used to infect immature bone marrow cells, and these cells were then transplanted into lethally irradiated recipients. All provirus-positive reconstituted mice were found to develop hematopoietic proliferative disorders and, in certain cases, overt leukemia--myeloblastic, myelomonocytic and T lymphocytic. In all cases expression of v-myc was high and the disease type did not correlate with the level of expression. We have isolated immortalized monocytes, myeloid progenitors and T lymphocytes from several of these mice and shown tumorigenicity in secondary syngeneic recipients. This system provides a model for investigating the progression from a pre-leukemic disease to malignancy. In addition, we describe a recombinant v-myc-containing retrovirus that directs high-level v-myc expression from the Mo-MLV promoter in all the hematopoietic cell types examined.

Animals↗
PubMed1991

Randomized, cross over study to assess patient preference for an acoustically modified hearing aid system.

It seems reasonable to postulate that if a patient has a hearing impairment at particular frequencies, selective amplification at those frequencies would be an advantage. Attempts have been made in the laboratory to show that when this is done scores on various audiometric tasks will improve. Whether such laboratory benefit will be preferred by patients in their daily life is another matter. Despite a lack of knowledge on this subject, modifications are frequently made to a hearing aid system in the expectation that this will improve auditory performance and hence be preferred by the patient. The most common modifications made to an ear level aid in the British National Health Service are adjusting the tone control and venting the ear mould with the aim of emphasizing the higher frequencies. A randomized crossover study was carried out in 83 first time hearing aid users with a mild to moderate hearing impairment to assess whether a hearing aid at the 'H' tone setting and with a 2 mm vented mould would be preferred by those with a more marked high frequency impairment. BE series aids were used so that any findings could be directly translated to NHS practice. No consistent preference for the modified system was identified when patients were subgrouped according to the overall slope (0.5 to 4 kHz) of their audiogram. However, when the slope between 0.25 and 1 kHz, which corresponds to the real ear effect of these modifications, was analyzed patients with a slope at these frequencies preferred the high-tone emphasis system (p less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Tympanometry in the detection of hearing impairments associated with otitis media with effusion.

The monitoring of children with otitis media with effusion ties up considerable resources in audiology departments. Impedance audiometry is frequently used when investigating these children. It has been shown to be highly sensitive in detecting middle ear effusion, but its value in identifying those children with a significant hearing impairment secondary to this is in question because of the wide range of hearing impairments possible with a type B tympanogram. This study quantified the sensitivity and specificity of impedance audiometry in detecting a hearing impairment greater than or equal to 25 dB HL due to otitis media with effusion. The subjects were 285 children of whom 20% had hearing thresholds greater than or equal to 25 dB HL. A peaked tympanogram (types A or C) virtually eliminated the possibility (98% confidence) of such a hearing impairment. A flat type B tympanogram was satisfactorily sensitive (93%) in detecting a hearing impairment, but non-specific (76%). The positive predictive value was 49%, i.e. 51% of ears with this type of tympanogram had hearing within acceptable limits. Assuming that a sensorineural impairment has been excluded and a population is being monitored for hearing impairment associated with otitis media with effusion, it is suggested that the presence of a peaked tympanogram indicates normal hearing, whereas those children with a flat tympanogram would require their hearing to be evaluated. Increased use of impedance audiometry to monitor children with otitis media with effusion would reduce the number requiring full pure-tone audiometry with a subsequent reduction in the workload of an audiology department.

Acoustic Impedance Tests↗
PubMed1991

New host and locality records for two protozoan (Myxosporea, Coccidia) parasites of marine fishes.

This is the first report of the myxosporean Ortholinea orientalis from Atlantic herring Clupea harrengus. It infects the kidney tubules and previously was known from Pacific herring Clupea pallasii and navaga Eleginus navaga in the White Sea and North Pacific Ocean. This is also the first report of the coccidian Eimeria raibauti from Norway pout Trisopterus esmarkii. It infects the epithelium of the pyloric ceca and previously was known only from poorcod Trisopterus minutus in the Mediterranean Sea. The new records are both from the northern North Sea.

Animals↗
PubMed1990

Three-generation reproduction study with dioctyl sodium sulfosuccinate in rats.

Groups of 30 male and 30 female rats (F0) were fed diets containing 0, 0.1, 0.5, or 1.0% dioctyl sodium sulfosuccinate (DSS) for 10 and 2 weeks, respectively. The F0 animals were then mated to produce an F1 litter. Groups of 30 male and 30 female F1 animals were fed the same dose levels for at least 10 weeks postweaning, and the breeding program was repeated to produce F2 animals. F3 animals were produced from F2 animals by the same procedure. The study was terminated with the F3 weanlings. Test diets were fed continuously throughout the study. All F0, F1, and F2 adults and F3 weanlings (one/sex/litter) were necropsied and given a macroscopic examination. There were no effects on reproductive function for parental animals of either sex during any of the three generations in this study. At the highest dose level (1.0% DSS), body weights were lower than those of controls during the premating phase for males in all three generations and for F1 and F2 females. Body weights for F1 and F2 males and females in the 0.5% dose group were also low during the premating phase. Pup weights on Lactation Day 0 were significantly lower than those of controls only for the high-dose group during the third generation. However, lower pup weight gains in the mid- and high-dose groups resulted in significantly lower pup weights on Day 21 for all three generations. Perinatal pup survival across three generations ranged from 96 to 100% for the control and treated groups. Pup survival ranged from 95 to 100% for controls, from 98 to 100% for low- and mid-dose groups, and from 91 to 99% for the high-dose group. There were no treatment-related mortality and antemortem or macroscopic observations. In summary, DSS administered in the diet to three successive generations of rats at levels of 0.5 and 1.0% caused a reduction in body weights for parental males in all generations and for F1 and F2 females. Pup weights at the 0.5 and 1.0% dose levels were also lower than those of the control in all three generations. However, the reduced body weights did not interfere with development of normal reproductive performance. DSS at levels up to 1.0% had no effects on the reproductive function of either sex in any generation and produced no treatment-related antemortem or macroscopic observations.

Animals↗
PubMed1990

Organization of the 5S rRNA genes in the soybean Glycine max (L.) Merrill and conservation of the 5S rDNA repeat structure in higher plants.

The 5S rRNA gene of the soybean Glycine max (L.) Merr. has been cloned on a 556-bp fragment of DNA and sequenced. This fragment contains two copies of the soybean 5S rDNA sequence, one intact and one truncated, separated by noncoding DNA. We have used this clone to investigate the organization of the 5S genes within the soybean genome and the extent of their methylation. Our results demonstrate that soybean 5S genes are clustered, organized into tandem repeats of 330 bp, and extensively methylated. Hybridization of the 5S sequence to Southern transfers of soybean DNA digested with BamHI reveals a striking ladderlike pattern. Hybridization of the soybean 5S sequence to a wide variety of plant DNAs results in similar patterns, suggesting that the 5S rDNA sequence, gene organization, and methylation pattern are conserved in many higher plants.

Base Sequence↗