The multi-disciplinary management of complex congenital and acquired tracheo-oesophageal fistulae

AIM OF THE STUDY

Complex tracheo-oesophageal fistulae (TOF) are rare congenital or acquired conditions in children. We discuss here a multidisciplinary (MDT) approach adopted over the past 5 years.

METHODS

We retrospectively collected data on all patients with recurrent or acquired TOF managed at a single institution. All cases were investigated with neck and thorax CT scan. Other investigations included flexible bronchoscopy and bronchogram (B&B), microlaryngobronchoscopy (MLB) and oesophagoscopy. All cases were subsequently discussed in an MDT meeting on an emergent basis if necessary.

MAIN RESULTS

14 patients were referred during this study period of which half had a congenital aetiology and the other half were acquired. The latter included button battery ingestions (5/7) and iatrogenic injuries during oesophageal atresia (OA) repair. Surgical repair was performed on cardiac bypass in 3/7 cases of recurrent congenital fistulae and all cases of acquired fistulae. Post-operatively, 9/14 (64%) patients suffered complications including anastomotic leak (1), bilateral vocal cord paresis (1), further recurrence (1), and mortality (1). Ten patients continue to receive surgical input encompassing tracheal/oesophageal stents and dilatations.

CONCLUSIONS

MDT approach to complex cases is becoming increasingly common across all specialties and is important in making decisions in these difficult cases. The benefits include shared experience of rare cases and full access to multidisciplinary expertise.

Validation of the Airway-Dyspnoea-Voice-Swallow (ADVS) scale and Patient-Reported Outcome Measure (PROM) as disease-specific instruments in paediatric laryngotracheal stenosis

OBJECTIVE

To validate the Airway-Dyspnoea-Voice-Swallow (ADVS) instrument as a disease-specific Patient-Reported Outcome Measure in paediatric laryngotracheal stenosis.

DESIGN

Prospective observational study.

SETTING

A quaternary referral centre for complex airway disease.

PARTICIPANTS

Forty-eight patients (30 males) with a mean age of 49 ± 49 months who underwent laryngotracheal surgery or microlaryngoscopy and bronchoscopy (MLB) following laryngotracheal surgery.

MAIN OUTCOME MEASURES

Airway-Dyspnoea-Voice-Swallow summary scale and Patient-Reported Outcome Measure (PROM), Paediatric Quality of Life (PedsQL) scale, Paediatric Voice Handicap Index (pVHI) and Lansky performance scale were administered to patients before and 6-8 weeks following airway examination/surgery.

RESULTS

Most patients (73%) had intubation-related subglottic stenosis, and 60% of patients had prior airway treatments. The majority of patients (77%) had more than one major chronic morbidity, and the commonest procedures were diagnostic MLB (49%), followed by airway dilation (29%). Cronbach-α value for the ADVS PROM was 0.71 overall and 0.85, 0.86 and 0.64 for the dyspnoea, voice and swallow domains, respectively. Rank correlations between Dyspnoea, Voice and Swallow summary scale and PROM scores were 0.83, 0.71 and 0.81, respectively (P < 0.0001). For those patients undergoing diagnostic MLB, pre- and post-examination scores were highly correlated (intraclass correlations >0.75). There was a significant rank correlation between ADVS PROM score and Lansky performance score (r = -0.68; P < 0.0001). There were significant correlations between PROM score and PedsQL (r = -0.57; P < 0.0001) and between voice domain of the PROM and pVHI (r = 0.78; P < 0.0001). There were strong correlations between Myer-Cotton stenosis severity and dyspnoea scale and PROM score (r = 0.68; P < 0.0001). There were significant differences in voice and swallow ADVS scales and PROM scores between patients with and without concomitant laryngeal/oesophageal pathology. Patient age and presence of high dyspnoea and swallowing PROM scores were independently associated with poorer quality of life and performance status.

CONCLUSIONS

These series of observations validate the ADVS instrument as a disease-specific outcome measure for paediatric laryngotracheal stenosis. Dyspnoea and swallowing dysfunction appear to have the greatest impact on quality of life. More widespread adoption of the ADVS instrument could help create a shared language for outcomes communication and benchmarking for children with this complex condition.

Nasal dermoids in children: a proposal for a new classification based on 103 cases at Great Ormond Street Hospital

OBJECTIVES

Nasal dermoids are rare developmental anomalies seen in children. This study reports the largest case series of 103 patients seen in a quaternary specialist unit over a 10-year period. We report the surgical and radiological findings and propose a new classification system, which clearly describes the extent of the lesions, thus allowing better surgical planning.

METHODS

A retrospective review of case notes was conducted. Data collection included demographics, initial presentation, site of lesion, pre-operative CT and MRI imaging, surgical procedure, intraoperative findings (including depth of lesion), complications and recurrence. Surgical findings were correlated with radiological findings.

RESULTS

A total of 103 patients were included in the study. The mean age at presentation was 29 months. 89% of children presented with a naso-glabellar or columellar lesion and 11% had a medial canthal lesion. All the patients underwent preoperative imaging and were treated with surgical excision. 58 children had superficial lesions, 45 had subcutaneous tracts extending to varying depths. Of these, 38 had intraosseous extension into the frontonasal bones, eight extended intracranially but remained extradural and two had intradural extension. There was good correlation between radiological and surgical findings. The superficial lesions were locally excised. The lesions with intraosseous tracts were removed via open rhinoplasty and the frontonasal bones drilled for access. Intracranial extension was approached either via a bicoronal flap and frontal craniotomy or the less invasive anterior small window craniotomy.

CONCLUSIONS

This report describes the largest published cases series of nasal dermoids. The cases demonstrate the presenting features and the variable extent of the lesions. The new proposed classification; superficial, intraosseous, intracranial extradural and intracranial intradural, allows precise surgical planning. In the presence of intracranial extension, the low morbidity technique of using a brow incision and small window anterior craniotomy avoids the more invasive and commonly used bicoronal flap and frontal craniotomy.

Single stage laryngotracheal reconstruction using endoscopic posterior grafting in isolated posterior glottic stenosis in children - how we do it

OBJECTIVE

Posterior glottic stenosis is a well recognised though rare condition. A wide range of treatment options have been proposed including endoscopic laser techniques and open techniques with grafting. The objective of this study was to present our experience of single stage laryngotracheal reconstruction with endoscopic technique of placement of posterior graft in isolated posterior glottic stenosis.

METHODS

This study was conducted at the Department of Paediatric Otolaryngology at Great Ormond Street Hospital, London. The senior authors (ALT, DMA) were involved in the management of two children with isolated posterior glottic stenosis operated on as single stage reconstruction.

RESULTS

The two children in this small series had isolated posterior glottic stenosis. The aetiology in both the cases was previous prolonged intubation. Both patients underwent a successful placement of the posterior graft endoscopically, though it was a challenging task because of space constraints. None of these children required an intra-operative or post-operative tracheostomy. There were no complications in these patients. At follow up endoscopic examinations, both these patients have had their airway widened successfully.

CONCLUSION

Single stage laryngotracheal reconstruction with endoscopic placement of posterior graft in cases with isolated posterior glottic stenosis is a good alternative to open surgical techniques, although is technically a challenging procedure.

Surgical excision as primary treatment modality for extensive cervicofacial lymphatic malformations in children

OBJECTIVE

There has been much recent focus on sclerotherapy treatment of lymphatic malformations with OK432. Surgical treatment however can have a number of advantages, including complete curative excision. The aim of this study was to evaluate the results of surgical excision as the primary (first) treatment for this condition. This group includes a number of children with very extensive disease as well as some with smaller lesions.

METHODS

Prospectively collected database with additional information from medical records of children with cervicofacial lymphangiomas treated over 10 years at a tertiary paediatric referral centre. For this study only children who underwent surgical excision as the primary treatment modality were included.

RESULTS

Total of 118 children with lymphatic malformations were treated under the care of the senior author over a 10 year period. Of these 53 patients, who underwent surgical excision as the primary treatment modality for cervicofacial lymphatic malformations were included in this study. Forty-one patients who underwent sclerotherapy as the initial treatment were excluded. Also excluded were 6 patients who underwent thoracic surgery and 18 who were treated conservatively. The majority of the patients (41, 77.3%) underwent only a single surgical procedure (36 - surgical excision, 5 - laser excision). At the first follow up after the primary surgery, the result was complete resolution of symptoms in 29 patients, near complete resolution in 13 patients (together 79.3%) and partial response in 11 (19.7%) patients. Twenty-three patients with disease localised only to the neck, all (100%) had a complete or near complete resolution of the disease after the primary surgery. Complete/near complete response was achieved in 98% cases with macrocystic disease, regardless of the location. Minor complications occurred in 11.3% patients. No permanent nerve weaknesses occurred.

CONCLUSION

Cervicofacial lymphatic malformations in children should be managed in a multidisciplinary setting. Surgery remains a very important treatment modality. The majority of patients (80%) in this study had complete or near complete resolution with one surgical procedure. Isolated neck lesions have the best outcomes (100% resolution in this study). Patients with macrocystic disease, achieved complete or near complete resolution in 97% of cases, regardless of the location. Some children with extensive disease will need multiple treatments. Surgical excision as the primary treatment modality in selected cases is safe and reliable technique and has good aesthetic and functional outcomes in experienced hands.

Porcine somatotropin alters body composition and the distribution of fat and lean tissue in the finisher gilt

The present study was designed to determine whether porcine somatotropin (pST) reduces whole animal and belly fat using dual energy X-ray absorptiometry and manual dissection. The study utilised 24 Large White × Landrace gilts selected at 16 weeks of age with an approximate liveweight of 80 kg and housed in individual pens. Gilts were stratified on liveweight into 8 blocks and 1 pig from each block was assigned to either 0, 5 or 10 mg per day of pST. Pigs were fed ad libitum a wheat-based diet containing 200 g crude protein, 10.2 g available lysine and 14.6 MJ DE/kg, to ensure that responses to pST were expressed. Feed intake and liveweight were measured on a weekly basis. An Hologic QDR4500A dual energy X-ray absorptiometer was used to determine lean, fat and ash composition of pigs initially and again 4 weeks later at the end of the experiment. After slaughter, the composition of the whole half carcass as well as the shoulder, ham, belly and loin primal cuts was determined with dual energy X-ray absorptiometry and verified with manual dissection. Daily pST treatment decreased feed intake (3440, 2710 and 2537 g/day for 0, 5 or 10 mg pST per day, respectively; P<0.001) and decreased feed conversion ratio (2.95, 2.18 and 2.03 g/g; P<0.001) even though there was no significant effect on daily gain. Pigs treated with pST deposited more lean tissue (620, 839 and 873 g/day; P<0.05) and less fat (384, 218 and 176 g/day; P<0.001) than control animals, but there was no effect of pST on ash deposition. As a consequence, pigs treated with 5 and 10 mg pST/day contained 5 and 9 kg less dissectible fat than control gilts, respectively. A dose dependent decrease in belly, loin, ham and shoulder fat was also observed, although the decrease in belly fat was more pronounced than for the whole carcass and other primal cuts. Overall, pST treatment has the potential to decrease carcass and especially belly fat in pigs and increase consumer acceptance of pork in markets that place a premium on carcass fat and lean yield in the belly region. The results determined with dual energy X-ray absorptiometry were confirmed by manual dissection.

Association of drug abuse with inhibition of HIV-1 immune responses: studies with long-term of HIV-1 non-progressors

Recreational drug use has been proposed to affect the course of human immunodeficiency virus (HIV) infections. To investigate the effects of substance abuse on HIV infections, we compared virus-specific cytotoxic T lymphocyte (CTL) responses and the expression of IL-16, TGF-beta1, and CXCR4 in three different cohorts of HIV-infected patients: (1) long-term nonprogressors (LT-NPs) of HIV infection who do not use recreational drugs; (2) nondrugs using normal progressors (NPs), and (3) drugs using NPs. Our results show that LT-NPs manifest increased CTL activity and IL-16 expression and decreased expression of TGF-beta1 and CXCR4 compared to NPs, regardless of recreational drug usage. Furthermore, drugs using NPs showed significantly lower levels of CTL and IL-16 expression and increased TGF-beta1 and CXCR4 expression compared to nondrugs using NPs. Our results suggest that recreational drug use may reduce CTL and IL-16 expression and increase the expression of TGF-beta1 and CXCR4, all of which may facilitate progression of HIV infections.

Human MUC1 mucin: a potent glandular morphogen

Human MUC1 mucin is a high-molecular-weight transmembrane glycoprotein, which is apically expressed in the majority of glandular epithelia. During embryonic development, changes in the pattern of MUC1 mucin expression coincide with the onset of glandular differentiation. This mucin is also frequently overexpressed and aberrantly glycosylated in carcinomas. To investigate the potential role of MUC1 mucin in morphogenesis, a full length MUC1 cDNA was transfected into murine mammary adenocarcinoma (410.4) and Madin-Darby canine kidney (MDCK) cells. This generated four clonal cell lines. Western blotting, FACS analysis, and immunohistochemistry confirmed expression of MUC1. All four MUC1-expressing clones demonstrated altered morphogenesis when cultured in three-dimensional type I collagen gels. While parental and vector control 410.4 cells formed compact spherical structures, the MUC1-expressing clones formed complex branching structures. Similarly, while parental and vector control MDCK cells formed small circumscribed colonies with a central lumen, the MUC1-expressing clones formed elongated tubules. MUC1 expression was also associated with reduced cellular cohesion and enhanced migration on type I collagen-coated surfaces for all except one of the clones, which expressed only low levels of MUC1 on the cell surface. These results show that MUC1 expression stimulates morphogenetic changes in two distinct epithelial cell lines. Taken together with previous observations on MUC1 expression in embryonic development and carcinomas, this finding suggests that MUC1 may induce changes in tissue architecture in both normal development and cancer.

Human MUC1 mucin: a potent glandular morphogen

Human MUC1 mucin is a high-molecular-weight transmembrane glycoprotein, which is apically expressed in the majority of glandular epithelia. During embryonic development, changes in the pattern of MUC1 mucin expression coincide with the onset of glandular differentiation. This mucin is also frequently overexpressed and aberrantly glycosylated in carcinomas. To investigate the potential role of MUC1 mucin in morphogenesis, a full length MUC1 cDNA was transfected into murine mammary adenocarcinoma (410.4) and Madin-Darby canine kidney (MDCK) cells. This generated four clonal cell lines. Western blotting, FACS analysis, and immunohistochemistry confirmed expression of MUC1. All four MUC1-expressing clones demonstrated altered morphogenesis when cultured in three-dimensional type I collagen gels. While parental and vector control 410.4 cells formed compact spherical structures, the MUC1-expressing clones formed complex branching structures. Similarly, while parental and vector control MDCK cells formed small circumscribed colonies with a central lumen, the MUC1-expressing clones formed elongated tubules. MUC1 expression was also associated with reduced cellular cohesion and enhanced migration on type I collagen-coated surfaces for all except one of the clones, which expressed only low levels of MUC1 on the cell surface. These results show that MUC1 expression stimulates morphogenetic changes in two distinct epithelial cell lines. Taken together with previous observations on MUC1 expression in embryonic development and carcinomas, this finding suggests that MUC1 may induce changes in tissue architecture in both normal development and cancer.

The impact of residual coagulant on downstream treatment processes

A series of jar tests were undertaken to optimise for suspended solids (SS) and phosphorus removal from raw wastewater. The residual metal concentration in the settled wastewater from the jar test experiments and the residual concentration from the optimum doses plus two higher doses were selected for investigation. The identified levels of residual metal were fed into a four lane activated sludge pilot plant to investigate the impact of metal concentration on (i) activated sludge performance and (ii) sludge production and characteristics. Optimum pre-precipitation studies showed residual ion concentrations of 1.68 and 3.46 mg l-1 for Fe(III) and Al(III) respectively. At these levels %P removal increased by approximately 25 and 60% respectively. NH3 removal decreased by approximately 20 and 34% in the activated sludge treatment process. Chemically dosed biomass had a significantly lower oxygen uptake rate than the control which was accompanied by a reduction in VSS; 10% for Fe(III) and 17% for Al(III). Changes in sludge characteristics were also observed. Chemical sludge had a greater settleability but a lower dewaterability than biological sludge. Sludge floc morphology was characterised which showed chemical flocs to be consistently smaller and visually denser than biological sludge flocs. The work presented in this paper considers the impact of residual iron and aluminium coagulants on downstream treatment processes.

Cytoplasmic induction and over-expression of cyclooxygenase-2 in human prostate cancer: implications for prevention and treatment

OBJECTIVE

To assess the level and morphological distribution of cyclooxygenase (COX)-1 and -2 in human prostates and to determine any association with the Gleason grade of prostate cancer. Materials and methods The study comprised 30 samples from patients with benign prostatic hyperplasia (BPH) and 82 with prostate cancer. Immunohistochemistry was used to assess the expression of COX-1 and -2, and 13 samples were also assessed using immunoblotting (six BPH and seven cancers).

RESULTS

For both BPH and prostate cancer, COX-1 expression was primarily in the fibromuscular stroma, with variable weak cytoplasmic expression in glandular/neoplastic epithelial cells. In contrast, COX-2 expression differed markedly between BPH and cancer. In BPH there was membranous expression of COX-2 in luminal glandular cells and no stromal expression. In cancer the stromal expression of COX-2 was unaltered, but expression by tumour cells was significantly greater (P = 0.008), with a change in the staining pattern from membranous to cytoplasmic (P < 0.001). COX-2 expression was significantly higher in poorly differentiated than in well differentiated tumours (P < 0.001). These results were supported by immunoblotting, which showed similar levels of COX-1 in both BPH and cancer, but four times greater expression of COX-2 in cancer than in BPH.

CONCLUSION

This is the first study to assess the co-expression of COX-1 and COX-2 proteins in benign and malignant human prostates, and showed the induction and significantly greater expression of COX-2 in cancer, which was also associated with tumour grade. The regular use of nonsteroidal anti-inflammatory drugs is associated with a reduced incidence of cancers. The present results provide the basis for a potential role for COX-2 inhibitors in the prevention and treatment of prostate cancer.

Matrix metalloproteinases and tumor invasion: from correlation and causality to the clinic

Tumor cell invasion is now viewed as dysregulated physiologic invasion. Investigators have started to define the molecular events that are involved in this process. We find that there are many functional similarities with molecular events involved in physiologic process such as angiogenesis and wound healing. Matrix metalloproteinase activity is a common denominator in these pathologic conditions and in normal responses. Studies using endogenous metalloproteinase inhibitors suggest that targeting matrix metalloproteinase activity may prevent tumor cell dissemination. The development and pre-clinical testing of novel, low molecular weight matrix metalloproteinase inhibitors support this concept and suggest that an exciting new era of cancer therapy is on the horizon.

Beta-globin haplotype analysis suggests that a major source of Malagasy ancestry is derived from Bantu-speaking Negroids

The origins of the inhabitants of Madagascar have not been fully resolved. Anthropological studies and preliminary genetic data point to two main sources of ancestry of the Malagasy, namely, Indonesian and African, with additional contributions from India and Arabia. The sickle-cell (beta s) mutation is found in populations of African and Indian origin. The frequency of the beta s-globin gene, derived from 1,425 Malagasy individuals, varies from 0 in some highland populations to .25 in some coastal populations. The beta s mutation is thought to have arisen at least five times, on the basis of the presence of five distinct beta s-associated haplotypes, each found in a separate geographic area. Twenty-five of the 35 Malagasy beta s haplotypes were of the typical "Bantu" type, 1 "Senegal" haplotype was found, and 2 rare or atypical haplotypes were observed; the remaining 7 haplotypes were consistent with the Bantu haplotype. The Bantu beta s mutation is thought to have been introduced into Madagascar by Bantu-speaking immigrants (colonists or slaves) from central or east Africa. The Senegal beta s mutation may have been introduced to the island via Portuguese naval explorers. This study provides the first definitive biological evidence that a major component of Malagasy ancestry is derived from African populations, in particular, Bantu-speaking Negroids. beta A haplotypes are also consistent with the claim for a significant African contribution to Malagasy ancestry but are also suggestive of Asian/Oceanic and Caucasoid admixture within the Malagasy population.

Stromal cell expression of components of matrix-degrading protease systems in human cancer

Components of matrix-degrading protease systems are in human cancer often expressed by tumour-infiltrating stromal cells. The cellular pattern of expression of these molecules appears to be unique for each type of cancer. In several cases there are similarities with patterns observed in nonmalignant remodelling processes in the same tissue. These findings indicate that the stromal cells actively participate in the process of cancer invasion. The implications of this new paradigm for cancer biology and cancer treatment are discussed.

Zidovudine pharmacokinetics in HIV-positive women during different phases of the menstrual cycle

STUDY OBJECTIVE

To examine the pharmacokinetics of zidovudine during the menstrual cycle in human immunodeficiency virus- (HIV-) positive women.

DESIGN

Open, unblinded study.

SETTING

A women's clinic for acquired immunodeficiency syndrome (AIDS) at a large medical center.

PATIENTS

HIV-positive women with a CD4+ cell count above 200/mm3, receiving long-term zidovudine therapy, with a history of regular menstrual cycles.

INTERVENTIONS

All patients received a 100-mg dose of zidovudine in the fasted state on three occasions.

MEASUREMENTS AND MAIN RESULTS

Zidovudine and zidovudine-glucuronide plasma concentrations were measured with radioimmunoassay to determine the pharmacokinetic characteristics during each menstrual phase. The drug's mean peak plasma concentrations (range 233-808 ng/ml) were 556 +/- 145, 385 +/- 132, and 495 +/- 143 ng/ml during the menstrual, late follicular-ovulatory, and luteal phases, respectively. Initially, plasma concentrations declined in a linear fashion from 0 to 4 hours, with a prolonged elimination phase in many patients after 4 hours. The mean zidovudine area under the curve was 886 +/- 156, 845 +/- 268, and 775 +/- 167 ng.hour/ml. The mean percentage of dose recovered was 44.2 +/- 26.0, 56.9 +/- 19.1, and 42.2 +/- 16.6, respectively.

CONCLUSIONS

The pharmacokinetics of zidovudine were not different during the three phases of the menstrual cycle; however, considerable intrapatient and interpatient variability was noted for many of the values.

Detection of extrachromosomal circular DNA sequences from tumor cells by an alkaline lysis, Alu-polymerase chain reaction technique

Extrachromosomal circular DNAs ranging in size from submicroscopic molecules of approximately 100 kb to cytogenetically resolvable structures of 1000+ kb called minute and double-minute chromosomes have been shown to harbor amplified genes in primary tumor cells, tumor cell lines, and drug-resistant cells grown in vitro. The presence of these molecules in transformed and malignant cells trends to reflect genetic instability and also suggests that role in tumor progression. Using a colon carcinoma cell line, we developed a technique to detect extrachromosomal circular DNA-specific sequences by Alu-polymerase chain reaction. Circular DNA was enriched by selective alkaline denaturation of genomic DNA. We have successfully performed this procedure with a minimum of 5 x 10(5) cells. The technique does not require any prior knowledge of the sequences located on the covalent circular DNA molecules for their detection. The procedure should be useful as a routine screen of primary tumor cells for the presence of extrachromosomal circular DNA and should permit the preparation of specific probes ot aid in their detailed characterizations.

The diagnosis and prognosis of autosomal dominant polycystic kidney disease

BACKGROUND

Autosomal dominant polycystic kidney disease is usually caused by a mutant gene at the PKD1 locus on the short arm of chromosome 16, but in about 4 percent of families with the disorder it is caused by unknown mutations elsewhere in the genome. The natural course of the disease in both genetic forms is not well characterized.

METHODS

We studied 17 families with autosomal dominant polycystic kidney disease to compare presymptomatic diagnosis by ultrasonography with diagnosis by genetic-linkage studies and to relate clinical variation of the disease to whether the PKD1 mutation was implicated.

RESULTS

In 10 families the disorder was found to cosegregate with polymorphic DNA markers flanking the PKD1 locus, in 2 families it did not, and in 5 families linkage could not be determined. In the 10 families with the PKD1 mutation, 46 percent of the members less than 30 years old who had a 50 percent risk of inheriting a mutation had renal cysts, as compared with 11 percent of the members of the two families without linkage (P less than 0.001). In the PKD1 families, all 67 diagnoses made by ultrasonography were confirmed by determination of the genotype as inferred from linkage. Forty of 48 members (83 percent) less than 30 years old who inherited the PKD1 mutation had renal cysts. All 27 members 30 years old or older who inherited the mutation had renal cysts, suggesting that the probability of a false negative diagnosis did not exceed 0.13 in this age group (P less than 0.05). The mean (+/- SE) age at the onset of end-stage renal disease among members of the PKD1 families was 56.7 +/- 1.9 years, as compared with 69.4 +/- 1.7 years among members with cysts in the families without linkage (P = 0.0025). Hypertension and renal impairment were less frequent and occurred later in the families without the PKD1 mutation.

CONCLUSIONS

At present, in most persons with a 50 percent risk of autosomal dominant polycystic kidney disease, imaging techniques are the only mode of reaching a diagnosis before symptoms appear. In such persons a negative ultrasonographic study during early adult life indicates that the likelihood of inheriting a PKD1 mutation is small. In the few who inherit a non-PKD1 mutation for polycystic kidney disease, renal failure is likely to occur relatively late in life.

An articulator modification for the planning of maxillary osteotomies

A device to facilitate accurate laboratory planning of maxillary osteotomies is described. The modification of a standard Dentatus articulator can easily be fashioned by a maxillofacial technician.

Utilization of 5-bromouracil by thymineless bacteria

Several thymineless Escherichia coli strains have been examined for their ability to replicate their deoxyribonucleic acid when bromouracil is substituted for thymine. The procedure we describe was used to identify a thymineless strain with characteristics relatively favorable to its use in bromouracil labeling experiments. In addition, mutants with an "absolute" thymine requirement could be easily distinguished from one with a "leaky" thymine requirement.

Influence of starvation for methionine and other amino acids on subsequent bacterial deoxyribonucleic acid replication

Billen, Daniel (University of Texas M. D. Anderson Hospital and Tumor Institute, Houston, Tex.), and Roger Hewitt. Influence of starvation for methionine and other amino acids on subsequent bacterial deoxyribonucleic acid replication. J. Bacteriol. 92:609-617. 1966.-A study has been made of the subsequent replicative fate of deoxyribonucleic acid (DNA) synthesized during amino acid starvation by several multiauxotrophic strains of Escherichia coli. Using radioisotopic and density labels and a procedure whereby total cellular DNA is analyzed, we have confirmed and extended a recent report that the DNA made during amino acid starvation behaves anomalously during subsequent DNA replication. When 5-bromouracil (BU) serves as the density lable, 40% or more of the DNA synthesized during starvation will subsequently fail to replicate during three cell generations. Selective amino acid effects were noted. In two methionine-requiring bacteria, methionine deprivation appeared to be of singular importance in influencing the subsequent replicative fate of the DNA made in its absence. When a non-BU density label (N(15), C(13)) was utilized, the effects of amino acid starvation were less obvious. Although the DNA synthesized during complete amino acid starvation in a methionine-requiring E. coli was subsequently more slowly replicated, most of the DNA was finally duplicated during three generations of growth. If methionine was present during starvation for other required amino acids, the subsequent replication rate of the DNA synthesized during this time was more nearly normal, and complete replication was observed. The results have been interpreted as indicating that DNA synthesized during amino acid starvation, and especially during methionine starvation, is somehow altered, and that BU substitution for thymine may interfere with the restoration of such DNA to its replicative state.

Physiological aspects of modification and restoration of chromosomal synthesis in bacteria after x-irradiation

Billen, Daniel (The University of Texas, Houston), and Roger Hewitt. Physiological aspects of modification and restoration of chromosomal synthesis in bacteria after X irradiation. J. Bacteriol. 90:1218-1225. 1965.-A study was made of the effect of amino acid deprivation or chloramphenicol on the character of postirradiation deoxyribonucleic acid (DNA) replication in bacteria with the use of radioisotopes and 5-bromouracil as a density label. CsCl density-gradient studies of DNA showed that postirradiation incubation of amino acid-requiring Escherichia coli in an amino acid-free medium interfered with continued linear chromosomal replication. In the presence of the required amino acids, linear chromosomal replication was shown to resume. Addition of chloramphenicol was found to prevent this resumption. Deletion of the required amino acids or the presence of chloramphenicol in a fully supplemented medium allowed the detection of altered DNA synthesis in bacteria at X-ray doses as low as 500 r. The character of the limited DNA made in the presence of the density label after irradiation is described. The results are interpreted as showing that the synthesis of a protein(s) is required for restoration of linear chromosomal replication in the irradiated cells.